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Have you ever stopped and wondered why humans still get goosebumps when they’re cold or scared? Or why we sometimes crave sugar even when we know it’s not healthy? 🤔 Believe it or not, these little quirks of ours are leftovers from our evolutionary past. Evolution isn’t something that stopped millions of years ago — it’s still quietly working behind the scenes, shaping the way our bodies behave, react, and survive today.

Let’s dive into some of the most surprising ways evolution still shapes our bodies — some might even make you smile (or cringe a little)! 😅

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The Goosebumps Mystery 🦢

When you feel cold or frightened, tiny muscles at the base of your hair follicles contract and make your hairs stand up. This reaction, called piloerection, once helped our ancestors trap air for warmth or appear larger to scare off predators.

Today, we don’t have enough body hair for it to serve any real purpose — yet our bodies still do it. It’s like your body saying, “Don’t worry, I’ve got this!” … even though, well, it really doesn’t anymore.

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Wisdom Teeth: Ancient Tools We Don’t Need Anymore 😬

Once upon a time, humans had bigger jaws and rougher diets full of raw meat, roots, and nuts. Wisdom teeth helped grind tough foods. But as we started cooking and using tools, our jaws got smaller, while our teeth… didn’t.

Now, these “extra molars” often cause overcrowding or pain — a classic example of evolution being a little slow to catch up.

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Appendix: A Tiny Organ with a Hidden Role 💚

For decades, people believed the appendix was completely useless — just an evolutionary leftover. But new research shows it actually plays a role in supporting good gut bacteria.

In ancient times, when infections wiped out intestinal bacteria, the appendix helped repopulate them. Today, with antibiotics and better hygiene, we don’t rely on it as much — but it still sits there, a quiet reminder of our microbial partnership.

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Craving Sugar and Fat: Evolution’s Old Trick 🍩

You know that irresistible pull toward sweet or fatty foods? That’s your ancient survival instinct talking! Early humans needed high-energy foods to survive harsh environments where food was scarce.

Fast forward to modern life — we’ve got grocery stores and fast food on every corner. But our brains still light up with joy when we taste sugar or fat, even though we don’t need all those calories anymore.

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The Tailbone: A Forgotten Balance Tool 🦴

Humans once had tails that helped with balance and mobility. Over time, as we started walking upright, our tails disappeared — leaving behind the coccyx, or tailbone.

You can’t wag it or use it to hang from trees anymore, but it still serves a small purpose — it helps anchor muscles and ligaments in your pelvic region. So even though it’s a leftover, it’s not completely useless!

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Body Hair: More Than Just Decoration 💁‍♂️

While most of us don’t rely on thick body hair for warmth anymore, it still has subtle roles. Hair helps sense movement on our skin (like bugs crawling — yuck 🕷️) and provides a bit of protection from sunburn.

Also, hair in specific areas, like armpits and the groin, plays a role in spreading natural body scents — something that might have been useful for attracting mates in the distant past.

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Our Eyes Still Show Our Animal Side 👁️

Ever noticed how your pupils dilate when you’re excited, or how your eyes get watery in emotional moments? These are deep biological reactions controlled by your ancient nervous system.

Even the way your eyes adjust to low light or react to movement traces back to survival instincts — detecting predators or prey in the dark.

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The Fight-or-Flight Response ⚡

When you suddenly get startled — maybe your phone drops or someone shouts your name — your body instantly floods with adrenaline. This is called the fight-or-flight response, an ancient survival mechanism.

Back in the wild, it helped our ancestors run from danger or prepare to fight. Now, that same system kicks in when you’re stressed at work or stuck in traffic — not quite life-or-death, but your body doesn’t know that difference.

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Standing Upright: A Double-Edged Gift 🧍‍♂️

Walking on two legs freed our hands and gave us the ability to use tools, but it also came with some drawbacks. Our spines, knees, and feet are under more pressure than ever before, which explains why back pain and posture problems are so common.

Evolution gave us balance and mobility — but it wasn’t a perfect design. It’s more like an ongoing experiment that hasn’t quite finished yet.

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Morning Sickness: An Evolutionary Defense 🤰

Scientists believe morning sickness during pregnancy evolved as a protective mechanism. The nausea helps mothers avoid potentially toxic foods during the early stages of fetal development when the baby is most vulnerable.

So while it feels unpleasant, it’s actually your body’s way of keeping the baby safe — pretty amazing, right? 💫

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Sneezing and Coughing: Ancient Self-Defense Reflexes 😷

Your body’s reflex to sneeze or cough isn’t just an irritation — it’s an ancient self-defense system. It evolved to expel harmful particles, bacteria, or viruses from the airways.

In the wild, that quick sneeze could mean the difference between staying healthy or catching a dangerous infection.

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The Shiver Reflex 🥶

When you shiver in the cold, your muscles are rapidly contracting to produce heat — a mini workout from your nervous system. Our hairy ancestors used this alongside their fur to stay warm. We’ve lost the fur, but the reflex remains.

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The Appendix of the Mind: Phantom Pain 🧠

Here’s something really interesting — people who lose a limb often report feeling sensations in that missing part. This phantom limb phenomenon shows how evolution shaped our brain’s body map.

Our brains are still wired as if every body part is intact, showing that evolution’s updates don’t happen overnight.

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Why We Still Yawn 💤

Yawning doesn’t just mean you’re sleepy — scientists think it helps cool the brain and keep you alert. This reflex likely helped early humans stay focused during times of danger or group vigilance. So the next time you yawn in class or at work, just tell yourself you’re “staying evolutionarily alert.” 😄

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Table: Summary of Evolutionary Traits Still Active Today

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Evolution Isn’t Over — It’s Just Slower Now 🧬

Many people think evolution stopped once we developed modern medicine and technology. But that’s not true — it’s still happening, just in quieter, subtler ways.

For instance:

• Some humans are developing resistance to certain diseases.

• Lactose tolerance in adults is still spreading in populations that rely on dairy.

• Wisdom teeth are slowly disappearing in some groups.

These changes prove evolution never takes a break — it just shifts direction as our environment changes.

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What This All Means for Us

The story of human evolution isn’t written in history books — it’s written in our bodies, in every heartbeat, sneeze, and strange reflex. Every quirk we have carries a whisper from the past.

So, the next time you get goosebumps, shiver, or crave something sweet, remember — that’s your inner caveman saying hello. 👣

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FAQs

Q1: Is evolution still happening in humans today?
Yes! Evolution continues through small genetic changes, adaptations to environments, and even resistance to modern diseases. It’s just a much slower process now.

Q2: Why do we still have body parts that seem useless?
Because evolution doesn’t “delete” old features — it modifies them over time. Some old traits just linger because they don’t cause harm.

Q3: Can evolution make us “perfect”?
No. Evolution isn’t about perfection — it’s about adaptation. It finds “good enough” solutions to help species survive in specific environments.

Q4: What’s an example of recent human evolution?
Lactose tolerance in adults and changes in our immune system are examples of evolution that have occurred within the last few thousand years.

Q5: Will humans keep evolving?
Absolutely. As long as environments change and humans reproduce, evolution will continue — just in ways we might not notice for thousands of years.

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✨ In Short:
Evolution isn’t just something from the past. It’s alive in us — in our bones, reflexes, and instincts. It shaped us before we were born, and it’ll keep shaping future generations long after we’re gone. 🌍

It’s amazing when you think about it — inside every one of us lies a complete manual, written in microscopic letters, that explains who we are, how we look, and even how our body works. That manual is called DNA. But DNA isn’t just a biological code; it’s a record of millions of years of evolution, migration, survival, and adaptation. And by reading it carefully, scientists are discovering lessons that modern humans can actually use — lessons about our health, behavior, ancestry, and even our future.

Let’s explore what our DNA really tells us — and how it can make our lives better today.

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Understanding the Basics: What DNA Actually Is

DNA stands for Deoxyribonucleic Acid. Think of it as a blueprint or instruction guide that tells every cell in your body how to function. Each cell in your body — from your skin to your brain — carries the same set of DNA.

Inside this DNA are about 3 billion base pairs, forming the code that determines your traits: eye color, height, metabolism, and even your risk for certain diseases.

Here’s a quick and simple breakdown 👇

So, in short: DNA is the storybook of life. And every one of us carries a slightly different version of that story.

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Our DNA is a History Book of Humanity 📜

You might think DNA is all about health and genetics, but it’s actually a time machine. When scientists analyze our DNA, they can trace where our ancestors lived, who they mixed with, and how they survived tough environments.

For instance, did you know that most people outside Africa carry a small percentage of Neanderthal DNA? These ancient cousins interbred with modern humans around 40,000–60,000 years ago. That leftover DNA still affects us today — influencing our immune systems, hair type, and even how we respond to sunlight!

It’s like our DNA is whispering ancient secrets: “Hey, you come from explorers who crossed deserts, mountains, and ice ages.”

So, one big thing modern humans can learn is resilience. Our ancestors faced unimaginable challenges — climate changes, scarcity, predators — and still survived. That strength is coded inside us.

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Health Insights Hidden in Our DNA 🧠💪

DNA can be your personal health coach — if you know how to read it.

Through genetic testing, we can identify risks for certain diseases like diabetes, cancer, or heart issues. Some people even use DNA insights to personalize their diet and exercise plans.

For example:

So, DNA isn’t destiny — but it’s a warning light that helps you make smarter choices. If your genes say you’re more likely to get heart disease, you can start managing your diet early.

And that’s the real magic: by learning from DNA, we can stop waiting for problems and start preventing them.

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How DNA Connects All Humans Together 🌍

One of the most beautiful things DNA teaches us is unity. Beneath the differences in skin color, language, or nationality, our genetic makeup is nearly 99.9% identical.

That means all humans — from any country, any background — share almost the same DNA. The differences that seem huge on the outside are only a tiny fraction at the genetic level.

Isn’t that powerful? It reminds us that humanity is one big family — we’ve just taken different paths over time.

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DNA and Ancestry: Tracing Where You Truly Come From 🗺️

Modern DNA testing kits can reveal your ancestry in fascinating detail. You can discover that you have roots in multiple continents — maybe 60% South Asian, 25% European, 15% East Asian.

This teaches us that identity is layered, not simple. You might feel connected to one culture, but your DNA can show you’re part of a much wider story.

It also helps break stereotypes. DNA proves that migration and mixing are natural human behaviors. We’ve always traveled, adapted, and blended — that’s how we evolved.

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DNA and Mental Health 🧩

Interestingly, DNA also holds clues to how our minds work. Some genetic variants influence how we handle stress, learn languages, or respond to trauma.

While environment plays a big role, understanding these genetic tendencies can help us manage our emotions better. For instance, if your DNA shows a sensitivity to stress, you can train your mind through meditation, mindfulness, or therapy.

So, in a way, DNA helps us understand ourselves more deeply — not just physically, but emotionally too.

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The Lesson of Evolution: Adapt or Fall Behind 🐾

Our DNA constantly changes. Every generation passes on tiny mutations, and over time, these create new adaptations. This process — evolution — teaches us a vital modern lesson: those who adapt survive.

Just like our ancestors learned to live in freezing climates or tropical forests, we too must adapt — but in different ways. Today, our challenges aren’t predators or hunger; they’re stress, pollution, and digital overload.

Our DNA reminds us that survival isn’t about strength — it’s about flexibility. Whether it’s adapting to technology, new cultures, or new ways of thinking, that same survival code still runs within us.

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DNA in Modern Science and Medicine 🧫

DNA isn’t just about learning our past — it’s shaping our future. Scientists now use DNA to design personalized medicine, cure genetic diseases, and even predict epidemics.

For example:

• CRISPR technology allows scientists to edit genes, fixing errors in our DNA like a spell-checker.

• Genomic research helps develop cancer treatments that target specific mutations.

• Forensic DNA analysis helps solve crimes and identify missing persons.

This shows how learning from our DNA isn’t just fascinating — it’s life-saving.

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DNA and Lifestyle: Why One Size Doesn’t Fit All 👟🍎

Ever wonder why a diet works for your friend but not for you? Or why some people can drink three cups of coffee and sleep fine, while others can’t handle one?

It’s your DNA.

Your genes affect how your body metabolizes food, reacts to caffeine, and stores fat. By learning this, we realize that health isn’t about following trends — it’s about understanding yourself.

So, instead of copying what others do, the modern human lesson is: listen to your body’s genetic blueprint.

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Ethical Lessons from DNA Discoveries ⚖️

With great knowledge comes great responsibility. As we learn more from DNA, we also face ethical questions.

Who owns your DNA data? How should it be used? Should employers or insurers access it?

These are big questions for our time. And they remind us that while DNA can unlock amazing benefits, we must handle it with care and privacy.

Learning from DNA isn’t just about science — it’s about ethics, respect, and humanity.

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Surprising Facts About Human DNA 🤯

Cool, right? It’s proof that DNA doesn’t just explain science — it connects us to every living thing.

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DNA Reminds Us of Balance ⚖️

Our ancestors lived closer to nature. Their DNA adapted to cycles of light, food scarcity, and physical movement. But today, our lifestyle is totally different — artificial light, fast food, and sedentary habits.

By studying DNA, we realize our bodies are still wired for a natural rhythm — sunlight, sleep, and real food. So maybe the best modern lesson from our DNA is this: go back to balance.

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The Emotional Lesson: You Are the Result of Survival ❤️

When you think about it, you’re the product of billions of years of successful survival. Every ancestor before you lived long enough to reproduce, pass on their genes, and keep the chain going.

That’s incredible. It means your DNA carries a record of strength, wisdom, and endurance.

So, whenever life feels hard, remember: your DNA is proof that you’re built to survive — because your story didn’t start with you, it started with the very beginning of life itself.

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FAQs About DNA and What We Can Learn from It

Q1: Can DNA really tell me who my ancestors were?
Yes! Modern DNA tests can identify your genetic heritage from different regions of the world. It can show your ethnic mix and even connect you to ancient populations.

Q2: Does my DNA decide my future health?
Not entirely. DNA gives you tendencies, not guarantees. Lifestyle, diet, and environment play a huge role in whether those tendencies actually turn into diseases.

Q3: Can DNA change over time?
Yes, small mutations occur naturally in every generation. These changes can sometimes lead to new traits or adaptations.

Q4: Is DNA testing safe and private?
It’s generally safe, but you should always read the privacy policy of any DNA company. Your genetic data is sensitive information.

Q5: Why is DNA important for science?
DNA helps scientists understand diseases, develop cures, track evolution, and even solve crimes. It’s one of the most powerful tools in modern biology.

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Final Thoughts 🌱

Our DNA is more than a code — it’s a message from the past, a guide for the present, and a promise for the future. It tells us that humans are connected, resilient, and ever-changing.

By learning from it, we can understand our health, embrace our shared humanity, and adapt to the challenges ahead.

So next time you think about DNA, don’t just imagine a double helix — imagine a story.
A story that began billions of years ago… and continues inside you, right now. 💫

What if you had a bone that was 50,000 years old? Now imagine being able to read the genetic instructions that gave that ancient person blue eyes, a tall frame — even diseases they might have carried. This isn’t science fiction. It’s taking place in labs around the world this very minute, and it’s upending everything we thought we knew about human history.

Today’s scientists can extract DNA from bones, teeth and even dirt that is thousands of years old. They can string together the genetic codes of our extinct cousins, like Neanderthals, and work out why some ancient civilizations crumbled while others triumphed. But the miraculous thing is this: none of it would be possible without state-of-the-art technology that wasn’t available as recently as two decades ago.

Today’s technology allows scientists to read genetic information that’s been shattered into millions of tiny pieces. They can clean dirty samples, piece together whole genomes from bits of DNA and run ancient genes up against their modern counterparts in ways that reveal astonishing secrets about the past. By enabling us to automatically identify patterns that humans would never spot, by allowing machines to sequence DNA faster than you can read this article, technology has created an opening into the ancient world our ancestors could only have dreamed of.

This is a behind-the-scenes look at this genetic detective work. You’ll learn the techniques scientists use to extract DNA from fossils, what machines they rely on to read ancient genetic codes and why this work is important for understanding not only where we came from but where we’re going. Join us on a journey through the intriguing rough-and-tumble world of technology-biotech-archaeology, where we’re rewriting history one gene at a time.

DNA Extraction: Getting DNA Out of Ancient Remains

The first obstacle for scientists is getting at the DNA locked up in old bones and teeth. “Think of ancient DNA like a book that’s been sitting out in the rain for hundreds of years — the pages are torn and faded,” said Eske Willerslev, a geneticist at the University of Cambridge. The challenge isn’t just that ancient DNA has broken down in the dirt; it’s highly fragmented and intermingled with dirt, bacteria and other contaminants.

Technology has come a long way since the 1990s and we now have extraction kits that do better with these ancient samples. Such tools rely on chemical solutions that carefully break DNA away from the mineral matrix of bones, rather than obliterating the delicate genetic material. Scientists in specialized “clean rooms” that resemble something out of a space station wear full-body suits to avoid contaminating the samples with their own DNA.

One new technology is called “petrous bone sampling.” The petrous bone is the densest region of your skull, located right behind your ear, and it just so happens this area holds onto DNA better than nearly any other part of the skeleton. Tiny drills similar to those used in dentistry are used by scientists to extract powder from this bone, and just a small amount (about the weight of a paperclip) can contain enough DNA to sequence a whole genome.

One innovative approach is even to collect and test samples of DNA from sediment — literal dirt — at archaeological sites. Our bodies are continually casting off cells, and in caves where ancient humans dwelled, some of the DNA they left behind ended up on the floor. Now, scientists no longer need bones to extract and identify this “environmental DNA.” This new technique has shown that some caves were definitely dwelling places for Neanderthals, even if no bones were found, expanding their knowledge of the sites before burial.

Sequencing Machines: Reading the Genetic Code

After scientists extract ancient DNA, they have to read it. And that is where the DNA sequencing machines come in. The latest technologies are technological marvels, capable of reading billions of DNA letters in a single day.

The most popular machines for ancient DNA are known as “next-generation sequencers.” Such devices do their job by duplicating millions of copies of DNA fragments and then reading them all at once. It’s as if a million people were reading random pages from that waterlogged book all at the same time and piecing together what the original text said using a computer.

Companies, such as Illumina, have created sequencers that are particularly optimized to analyze degraded DNA. Their machines are capable of reading very short pieces — sometimes just 30-40 DNA letters long — which is ideal for ancient samples in which the DNA has fragmented into tiny chunks. The system relies on fluorescent markers that shine different colors depending on the letter of DNA they signal (A, T, G or C) — the color patterns are then photographed by cameras and decoded for genetic sequence information.

What used to cost years and millions of dollars now takes days and costs a few thousand dollars. Preceded by the Human Genome Project (which was finished in 2003, at a single-genome cost of about $3 billion and with each genome taking 13 years to sequence), modern machines can sequence several ancient genomes in a week for a small fraction of that price.

Bioinformatics: Making Sense of the Data

Sequencing ancient DNA generates mountains of data — frequently terabytes. This is where bioinformatics comes in. Bioinformatics is the process by which a bunch of research data can be put into a computer program and turned into something interpretable.

Researchers rely on a number of essential software tools. First, they filter out contamination. The ancient bones themselves are typically coated in bacterial DNA, fungal DNA and sometimes human DNA from people who handled the artifacts over the years. The ancient individual’s DNA can be untangled from contaminants using intricate algorithms.

One popular program, “mapDamage,” analyzes footprints of DNA damage that accumulate over time. Ancient DNA comes with a kind of damage pattern at the ends of fragments and if the program can see such a pattern it’s old, not modern contamination.

Another challenge is assembling fragments. Now imagine if you had a jigsaw puzzle, but 90% of the pieces were gone and those that remained were shattered into tiny pieces. That’s what it looks like, ancient DNA. With software programs, the ancient fragments can be compared to reference genomes of modern humans and other species, piecing together where each fragment belongs. Applications such as “BWA” (Burrows-Wheeler Aligner) and “bowtie” have been developed to help map these short, damaged DNA fragments on reference genomes.

Artificial Intelligence: Unearthing Patterns Among Ancient Genes

Artificial intelligence and machine learning are game changers in ancient DNA. Those may notice patterns or make connections that human researchers might require years to discover, if ever.

Machine learning helps determine which genetic mutations are linked with what traits. For instance, AI has enabled scientists to decode which of the genes could have made Neanderthals — with their prominent brow ridges or barrel-shaped chests — stand out. The algorithms contrast thousands of genetic variants between ancient humans and those living today, for each line of descent estimating which differences probably altered physical appearance, disease risk or other traits.

Deep learning networks are even being trained to predict what our ancient ancestors looked like based on their DNA. We can’t generate perfect reconstructions, but A.I. can make educated predictions about skin color, hair color, eye color and facial features by examining genes that play a role in these traits in modern populations.

One promising application is to use A.I. to find ancient DNA in samples where traditional methods are stymied. Researchers have taught such types of neural networks how to read patterns of ancient DNA damage, even in the presence of heavy contaminations. This has enabled them to sequence the genetic material from samples that had, up until now, been far too degraded for analysis.

Comparative Genomics: Bridging the World of Ancient and Modern DNA

Scientists also compare ancient genomes with those of modern ones, thanks to technological developments. Massive genetic databases now hold the genomes of hundreds of thousands of people around the world, and powerful computer systems can compare the remnants with this vast collection in hours.

This cross-comparative method has uncovered interesting findings. Technology, for example, revealed that the vast majority of non-African people today possess 1-2% Neanderthal DNA. Researchers arrived at this conclusion by comparing ancient Neanderthal genomes to modern human genomes and looking for fragments using statistical software that derived from interbreeding tens of thousands of years ago.

Advanced programs determine genetic links among ancient and modern populations. They can figure out, for instance, that contemporary Europeans descend from three distinct ancestral populations who mixed together over millennia or that Native Americans share a common genetic lineage with ancient Siberians who roamed the Arctic 24,000 years ago.

Preserving Technology: Keeping Ancient DNA Alive

Current storage technology is crucial for maintaining valuable ancient DNA samples. After being extracted, DNA is kept at very cold temperatures — typically minus 80 degrees Celsius or even colder. Specialized freezers keep those temperatures steady, and automated systems send alerts if the temperature begins to rise.

Some facilities store samples long term in liquid nitrogen tanks at minus 196 degrees Celsius. At these cold temperatures, chemical reactions virtually stop and DNA is preserved indefinitely. There are some research centers that keep “biobanks” of thousands of ancient DNA samples — libraries of genetic information for researchers across the globe to study.

Digital storage is equally important. Data from ancient samples of genetic sequences are kept in huge databases with a multiplicity of backups. Cloud technology means that scientists from around the world can use and analyze this data without ever having to handle the physical samples, which is particularly important when it comes to sharing unique archaeological materials.

Carbon Dating and DNA Testing in Collaboration

It is not exactly reading the DNA, but radiocarbon dating technology proves to be a great helpmate to ancient genetics. Accelerator mass spectrometry can date the age of a sample much earlier using far smaller samples — sometimes a few milligrams of bone.

This technology is important because the precise age of a sample can tell scientists when different populations existed and how they might have come into contact. For instance, exacting dating helped to establish that modern humans and Neanderthals had, in fact, overlapped in Europe for several thousand years — which would have made interbreeding between the two groups possible.

New methods can also recover both DNA and dating information from the same bone chip, thus avoiding the loss of valuable archaeological material.

Technologies Enabling the Study of Ancient DNA

Technology	What It Does	Why It Matters
Next-Generation Sequencing	Reads millions of DNA fragments at once	Makes it cheap and fast to sequence ancient genomes
Clean Room Facilities	Prevent modern DNA from contaminating old stuff	Ensures ancient DNA stays clean of other people’s DNA
Bioinformatics Software	Analyzes really big piles of genetic data	Lets you know what’s genuine ancient-genome data, filters out contamination
Machine Learning Algorithms	Detect patterns in the genetic information	Predict traits and relationships from fragmentary DNA
Petrous Bone Sampling	Get DNA from skull bones dense with hard bone	Higher-quality DNA than other parts of the body
Environmental DNA Extraction	Grabs strands left in sediment	Helpful when there are no old bones to be had
Cryogenic Storage	Preserves samples at super-low temperatures	Keeps everything cold enough that damage won’t set in before scientists have studied them all

Real-World Applications: What Ancient DNA May Reveal

This technology is not all just for curiosity. The study of ancient DNA has tangible, real-world implications that resonate with our contemporary life. Researchers have found genes that offer some populations partial protection against particular diseases, such as malaria. For instance, the study of ancient genomes has uncovered genetic variants that protected against certain infections, information that could in turn inform new vaccines or therapies.

Ancient DNA has also contributed to resolving archaeological mysteries. Technology revealed that the enigmatic Denisovans, present so far only by a few bone fragments in Siberia, were interbreeding with ancient human ancestors and passing along genes that help modern-day Tibetans survive at high altitudes.

For indigenous peoples, ancient DNA methods of analysis may offer scientific evidence that can underpin historical assertions about territories or validate oral accounts transmitted through centuries. And it can facilitate returning repatriated ancient remains to descendant communities based on genetic ties.

Upcoming Innovations

Technology continues advancing rapidly. “Portable sequencers” are also being developed that can be carried out into the field, so DNA analysis can begin at the archaeological site. Roughly the size of smart phones, these gadgets could deliver preliminary genetic information within hours of being excavated.

New chemical methods can help restore broken-down ancient DNA, essentially “fixing” the decay that happens over thousands of years. That might unleash genetic information from samples that had been too damaged to read.

Ancient DNA analysis could soon be transformed by quantum computing. These supercomputers could solve some of the most complicated genetic puzzles fairly quickly – exponentially faster than existing systems, unearthing insights that today’s tech simply can’t see.

Learn more about ancient DNA research at the Max Planck Institute, one of the leading centers for evolutionary genetics.

Challenges Technology Still Faces

Despite remarkable advances, challenges remain. DNA breaks down over time, and there is a threshold to how far back into the past scientists can look for genetic clues. The oldest DNA sequenced thus far has been about 1.2 million years old, from the teeth of mammoths preserved in Siberian permafrost. For the majority of samples, DNA is unreadable after perhaps 50,000-100,000 years.

Tropical and warm weather are an added challenge, since heat and humidity cause DNA to degrade more quickly. That’s because scientists have far less genetic data from ancient populations in Africa, Southeast Asia and South America than they do from cold-weather climes like Europe and northern Asia.

Ethical questions also arise. Who owns ancient DNA? Should scientists remove DNA from burial sites without the consent of descendant communities? Technology has the potential to reveal private details about ancient peoples — such as genetic diseases or family relationships — that the modern-day descendants of those people may not want made public.

Frequently Asked Questions

What is the age of the oldest sequenced DNA?

The oldest DNA ever successfully sequenced comes from mammoth teeth recovered from Siberian permafrost, and dates to around 1.2 million years ago. For human DNA, they have sequenced genomes from people up to about 45,000 years old. When and for how long DNA survives depend on the environment — cold, dry environments preserve DNA far better than warm, humid ones.

Can scientists use ancient DNA to bring extinct species back to life?

Although it’s an idea popularized by movies such as Jurassic Park, today scientists cannot truly bring extinct species back. DNA degrades too much over thousands of years to obtain a still functional complete genome. But researchers are also working on “de-extinction” projects for recently extinct species, like woolly mammoths, by editing the DNA of modern elephants to incorporate mammoth genes. This is not going to give you a real mammoth, it is giving you something adapted for the cold.

How much does it cost to sequence the genome of an ancient skeleton?

Costs have dropped dramatically. The first ancient genome might have cost many millions of dollars to sequence, whereas a full ancient human genome can now be sequenced for between $1,000-$5,000 depending on DNA quality. The better-preserved the sample is, the cheaper they are to analyze because more feasible data can be extracted from it. It’s laboratory work for DNA extraction and expert analysis, which is the most expensive part of all this.

Why does ancient DNA fragment into short bits?

DNA decomposes over time by chemical means. Chemical bonds that link strands of DNA together are in turn broken by water, oxygen and enzymes. Think of DNA as a rope — and over time, the rope frays, breaking up into smaller and smaller pieces. This process is accelerated by temperature fluctuations, acidity in the soil, and bacterial activity. DNA fragments in ancient samples are generally only 30-100 base pairs whilst those of modern organisms can stretch to the millions.

What can ancient DNA research reveal about an individual person from history?

Yes, but with limitations. From ancient DNA, scientists can infer biological sex, approximate age at death, ancestry and some physical traits. They can also detect familial relations between a group of people who are buried together. But a name, or language, or habits of culture cannot be discerned from DNA. For instance, scientists sequenced DNA from Richard III of England and then confirmed his identity via living relatives; the DNA alone didn’t divulge that he was a king — historical evidence and archaeology did.

Can ancient DNA be extracted only from bones and teeth?

Bones and teeth are the typical sources — they preserve DNA well — but scientists have extracted ancient DNA from other materials. DNA can persist in hair shafts for thousands of years. Mummified tissue occasionally yields DNA. They have even recovered human DNA from ancient chewing gum, dental calculus on teeth and soil from cave floors where ancient people lived. There is thus specific extraction for each source.

Winding Up the Genetic Time Machine

The technology that is aiding scientists in unlocking ancient genes stands as one of the most interesting frontiers now for scientific research. What appeared impossible only decades ago — to read the genetic instructions of people who lived tens of thousands of years in the past — has become routine work for labs around the world. These technologies have turned scattered bone fragments into detailed genetic portraits and shown how ancient populations moved, adapted and interbred — events that made us who we are today.

From high-end sequencing machines that read billions of DNA letters every day to artificial intelligence programs that are able to spot patterns that human eyes cannot detect, each technological advance takes us a step closer to understanding our distant past. These detective tools have revealed that modern humans harbor Neanderthal genes, that enigmatic extinct groups like Denisovans bequeathed DNA throughout our genome, and that our ancestors lived through ice ages in part thanks to genetic changes they passed down to us.

But this is only Step 1. As technology advances, we will get information out of even older samples, from places where DNA preservation isn’t great because it’s a warm environment, and from newer materials that haven’t occurred to us to look at. Every discovery has led to new questions: Whom else will we find among our extinct human relatives? How did ancient genetic mutations help protect populations from plagues and famines? What can the DNA of ancient babies teach us about fighting modern disease?

As the rubber meets the road between technology and ancient genetics, it’s not just about looking backward. It’s about knowing ourselves more fully. Every sequence of an ancient genome in some way fits another piece in the puzzle of human evolution — helping us not just to know our origins, but to comprehend what makes us human in the first place. And as these technologies grow increasingly powerful and accessible, they hold the potential to continue offering up surprises about our ancient ancestors and their extraordinary journey that ended — at least for now — something close to where we stand today.

Now, picture yourself the possessor of a small sliver of bone from an animal that lived 50,000 years ago. Contained within that bone, hidden like a coded message, is DNA — the instruction manual for life. For years, researchers had dreamed of deciphering those ancient genetic codes, but the technology just wasn’t there. Today, that dream is a reality. Today’s advanced machines and savvy methods make it possible for researchers to extract genetic information from the bones, teeth and even dirt that is thousands of years old. The discovery is rewriting everything we thought we knew about human history, extinct animals and the story of life on Earth.

The leap from ancient dust to decoded DNA sequences is truly miraculous. But it is a blend of state-of-the-art computer power, laboratory precision and detective work worthy of Sherlock Holmes. Now scientists can answer what once seemed like impossible questions: What did Neanderthals actually look like? Why did woolly mammoths become extinct? So how did primitive humans survive so many deadly diseases? The solutions lie hidden in ancient genes, and we’re using technology to uncover them.

Why Ancient DNA Is So Hard to Read

Before we discuss our technology, let’s consider the problem. Ancient DNA is not like the fresh DNA scientists pull from a cheek swab or blood sample. When a living plant or animal perishes, its DNA begins breaking down virtually from the moment of death. Imagine DNA as a long ladder consisting of millions of rungs. With each passing moment, this ladder becomes chopped into smaller and smaller pieces. Thousands of years on, rather than a fully assembled ladder, you’re left with minuscule fragments — it’s like trying to read a book that’s been shredded into confetti.

But that’s not the only problem. Ancient DNA gets contaminated easily. Bacteria, fungus and contemporary DNA from people who came into contact with the sample can all get mixed in too. It’s like trying to read any one particular letter in a dictionary where somebody has interspersed random pages from 50 other books. That’s what scientists confront if they want to study ancient genes.

The environment also matters tremendously. DNA does not last well in heat, moisture or light. A mammoth preserved in Siberian ice for 20,000 years may have reasonable DNA however. A dinosaur bone, 65 million years old? Forget it — the DNA is utterly lost. By common consent among scientists, DNA does not survive more than one million years — and even that’s pushing it.

The Game-Changing Technologies

Next-Generation Sequencing Machines

The most revolutionary advance came with a type of machine known as next-generation sequencers. These devices can read millions of DNA fragments simultaneously, an excellent approach for ancient samples whose DNA is already fragmented.

DNA sequencing technology from the 1990s, for example, could read just one DNA fragment at a time. It was slow and costly and took reams of DNA, which ancient samples just don’t have. Modern sequencers work differently. They can pull all those tiny DNA pieces, read them at once and use computer programs to try to figure out how they fit together, a bit like trying to piece together a jigsaw puzzle with millions of pieces.

Companies such as Illumina have developed machines that can sequence a whole human genome in under 24 hours for about $1,000. Nearly two decades ago, the equivalent job took years and cost $100 million. This precipitous fall in cost and time now means that scientists can study ancient DNA from hundreds or even thousands of samples rather than just a few.

PCR Amplification: More for Less

One of the most basic but also most critical technologies is known as polymerase chain reaction, or PCR. This method is like a molecular photocopier. With just a microscopic speck of DNA — even a single strand of it — PCR can produce billions of copies.

Here’s how the process works: Scientists mix certain “reagents” into the DNA sample and then heat up and cool down the mixture over and over. And each time they cycle through this process, the quantity of DNA doubles. After 30 cycles, you’ve got over 1 billion copies from a single original. This is especially useful for ancient samples in which very little DNA can be obtained.

However, PCR has a catch. It can also amplify contaminants of DNA, which is why scientists have to be extremely careful about keeping their samples clean.

Computers That Connect the Dots

It is one thing to be able to read ancient fragments of DNA; it is another to tease out what they mean. Powerful computer algorithms come here into play. These programs compare the ancient DNA sequences to databases with DNA from modern animals and humans.

The computer hunts for matching or overlapping pieces, slowly assembling them one by one to form an image of what the complete ancient genome would have looked like. It’s as if you had software that could stare and stare at thousands and thousands of pieces of the puzzle, figure all of them out, even when some of the pieces are bent, or partially missing.

And the latest machine learning and artificial intelligence technology are making these programs even smarter. Now they can tell with greater confidence what’s real ancient DNA, and what is contamination instead, and guess more confidently at missing pieces by reasoning from the DNA of close relatives.

Pulling DNA Without Destroying Fossils

Previously, museum curators would wince when geneticists requested samples. Prior methods required grinding up or drilling into bone and tooth — destroying irreplaceable fossils forever. This has changed drastically with new technology.

Non-Destructive Sampling Methods

Nowadays, scientists have techniques that require much smaller samples. At other times, from just a scant scraping of powder from the surface of a bone they are able to extract DNA. In some cases, they don’t even need the fossil — DNA can be obtained from sediment near where ancient creatures lived.

Scientists in caves in Europe have managed to get human and animal DNA from dirt on cave floors. These samples of sediment contain small pieces of skin, hair and other biological material that were left behind by ancient creatures. It’s akin to reading the genetic history of a place without requiring any bones whatsoever.

The Clean Room Revolution

For contamination control, scientists now labor in special clean rooms that could easily pass for props in a science fiction film. They all are in full-body suits, masks and layers of gloves. The air is constantly filtered, and rooms are maintained at a positive pressure so that outside air doesn’t seep in.

These labs also kill any contaminating DNA with UV light before the samples arrive. Much of the equipment is sterilized, and scientists are known to test themselves so that they don’t include their own DNA in the samples that they study.

What Ancient Genes Have Revealed

There’s more than just impressive technology here — there have been breathtaking discoveries that are rewriting history of humanity.

The Neanderthal Inside Us

One of the most surprising ones fell out when scientists sequenced the Neanderthal genome. They found that nearly everyone alive today has some Neanderthal DNA. If you have ancestors from outside of Africa, about 2 percent of your genome derived from Neanderthals.

This showed that ancient humans didn’t just meet Neanderthals — they had children with them. Some of those children survived and passed on Neanderthal genes that survive in people to this day. Some of those genes influence our immune systems, our skin color and our risk for certain diseases.

The Denisovans: Discovered Through DNA

Even more startling, scientists identified a previously unknown type of ancient human purely through its DNA. In a cave in Siberia, scientists found a small finger bone. The DNA was human-like, however it differed from that of both modern humans and Neanderthals. They named this new group Denisovans.

And here’s the wild thing: We know that Denisovans were really a thing, we know what their genes looked like — and we know that some people living today (especially in Southeast Asia and Oceania) carry actual Denisovan DNA. Yet we still have only a few scraps of actual Denisovan fossils. They were found by their genes before anyone saw their bones.

Bringing Back Extinct Animals?

Now, scientists have sequenced the genomes of woolly mammoths and saber-toothed cats — and even those of horses in Asia that lived more than 700,000 years ago. This raises a fun question: could we de-extinct them?

Some scientists are already on the case. In a controversial experiment, they have set out to edit the DNA of elephants with a tool that could allow them to add mammoth genes so their bodies can produce “mammoth hemoglobin,” which the researchers speculate will help them survive in arctic temperatures. We’re not there yet, but the technology is available to try that right now.

The Technology Timeline

Year	Technology/Discovery	Impact
1984	First ancient DNA extraction	Demonstrated preservation of ancient DNA
1993	Perfecting PCR for ancient samples	Enabled amplification of small amounts of DNA
2005	Invention of next generation sequencing	Allowed large-scale studies of ancient DNA to be conducted
2010	Publication of first Neanderthal genome	Showed human interbreeding with Neanderthals
2012	Sequencing the Denisovan genome	Discovered new types of humans
2013	Sequencing horse DNA from 700 thousand years ago	Established record for oldest DNA sequenced
Recent years	CRISPR gene editing achieved	Made de-extinction concept feasible
Recent years	Extracting and analyzing DNA preserved in dirt	Eliminated a need for actual fossils in some instances

How Scientists Read Ancient Genes, Step by Step

The real process scientists follow when they get their hands on an ancient sample, though?

Step 1: Sample Preparation and Selection

Scientists are judicious about which fossils to sample. They seek out well-preserved bones or teeth kept in good storage. A dense bone in the skull called the petrous bone and teeth are favorites because they tend to preserve DNA better than other bones.

Upon return to the clean room, they then cleaned the sample exterior to remove surface contamination. Occasionally the facility workers will just cut away the outer layer entirely. Then they grind a tiny bit to powder.

Step 2: DNA Extraction

The powder is combined with special chemicals that crack open old cells and release whatever DNA is left inside. The result is a solution that theoretically contains long lost fragments of ancient DNA floating around in the liquid.

The scientists then filter out the DNA and chemically remove it from all of everything else — minerals, proteins, other cellular detritus. What you have is your strong solution of DNA fragments.

Step 3: Library Preparation

This is where it becomes technical. Researchers link specially designed molecular “adapters” to each DNA fragment. The adapters are like name tags to help the sequencing machine grab and read each piece of DNA. Such a collection of tagged genomic fragments is known as a library.

Step 4: Sequencing

The library is loaded onto the next-generation sequencing machine. Millions of DNA fragments get read at once inside. For each of the four chemical letters that make up DNA (A, T, G and C), the machine notes its identity. Then, after a few hours or days, the machine spits out data files with billions of these letters.

Step 5: Bioinformatics Analysis

Now the computers take over. Powerful programs match the ancient DNA sequences against reference genomes from modern and other ancient species. The software determines what species a sample came from, eliminates contamination and stitches the fragments into longer sequences.

Depending on the quality of the sample and how complex the questions scientists are asking, this step can take weeks — or months.

Step 6: Interpretation

Finally, scientists examine the results and decipher what they signify. They could compare the ancient genome with modern genomes to understand how species evolved. They may search for particular genes that affect appearance, behavior or resistance to disease. They may estimate when distinct populations separated or rejoined.

Challenges That Still Remain

Yet for all of this amazing progress, scientists continue to encounter serious hurdles.

The Age Limit

DNA doesn’t last forever. Even under ideal circumstances, DNA degrades with time. The general consensus among experts is that once you go beyond about a million years, DNA becomes too degraded to salvage. Which means we will never be able to sequence dinosaur DNA, no matter what “Jurassic Park” might have you believe.

Ethical Questions

As the technology becomes more advanced, the ethics become more urgent. Is it ethical for us to sequence ancient human DNA without the consent of descendants? Is it ethical to possibly resurrect extinct animals? Who owns ancient DNA and what can be done with it?

Some indigenous communities have expressed concerns about scientists harvesting and analyzing DNA from the remains of their ancestors. They say this contradicts their culture and should not be done without their consent.

Cost and Access

Sequencing ancient genomes, even as the price has plummeted, is expensive. The equipment and expertise can be beyond the means of many museums or research institutions. That means most ancient DNA work takes place in — and for the benefit of — rich countries, even though significant fossils exist throughout the world.

Ancient DNA Things to Come

The field is moving so quickly that what sounds impossible today could be the norm a decade from now.

Portable DNA Sequencers

Companies are racing to create DNA sequencers that are small enough to carry in a backpack. Picture paleontologists out in the field with the capacity to test whether a fossil contains DNA and then make an on-the-spot decision about whether to respectfully extract it. This innovation holds the potential to transform how fieldwork is conducted.

Better Computer Models

Artificial intelligence is improving at creating DNA sequences for biotechnology. Future AI may be able to reliably predict missing sections of ancient genomes, pushing our extent even further into the past.

Ancient Proteins and Epigenetics

They are also developing technology to study ancient proteins, which can live on much longer than DNA — sometimes millions of years longer. Although proteins don’t store as much information as DNA does, they can tell us about ancient life.

Scientists are also starting to look at epigenetics from ancient samples — chemical changes to DNA that cause genes either to be switched on or off. That might provide a clue about the lives of long-lost creatures that DNA alone cannot illuminate.

Why This Matters for Everyone

You may be asking yourself why you should care about ancient DNA research if you are not a scientist. The answer is that such discoveries change the way we see ourselves and our place in nature.

Ancient DNA studies have shown that human history is far more complicated than we thought. We didn’t just evolve in Africa and get out and spread around the world. Rather, we interbred with members of other human species, quickly adapted to new environments, made it through cataclysmic events that killed off other species.

This also aids in medical uses. By investigating how early humans coped with diseases, scientists can gain insight into our immune systems today. Some of the genes that helped our ancestors fend off infections those generations ago are now the ones that make some susceptible to autoimmune diseases.

And for conservation, ancient DNA helps us to understand how animals have responded to climate change in the past and to human pressures. This understanding could help us save endangered species right now. Learn more about ancient DNA research and conservation efforts.

Frequently Asked Questions

What is the oldest DNA that has been sequenced?

The oldest verified DNA is from the teeth of mammoths discovered in permafrost beneath Siberia and dates to about 1.2 million years ago. Still, researchers argue about whether DNA can survive tens of thousands of years beyond this age.

Can scientists actually resurrect an extinct animal using that ancient DNA?

Not exactly. Although scientists are able to read ancient DNA sequences, they aren’t yet able to take that information and “print out” a living mammoth. But they may be able to engage in gene-editing by adding crucial mammoth genes into the DNA of other living relatives, such as elephants, to produce a hybrid animal.

Why is it that we can’t sequence any dinosaur DNA?

Dinosaurs died out 65 million years ago. Even under the best possible preservation conditions, there is an upper limit to how long we can expect DNA to last: about 6.8 million years or so. Any reports of dinosaur DNA are either errors or hoaxes.

How can scientists be sure that ancient DNA is not contamination?

Ancient DNA has distinctive patterns of damage that modern DNA doesn’t. Scientists search for such patterns and even sequence the same sample several times in different labs to verify results.

Can ancient DNA show us what extinct animals would have looked like?

Yes, to some extent. Genes in DNA determine how cells function and are encoded with traits like color, size and physical capabilities. Scientists can use comparisons between ancient DNA and modern relatives to make educated guesses about what the individuals looked like.

Is it ethical to sequence DNA in ancient human remains?

This is debated. Many scientists feel they should consult and get permission from descendant communities before studying ancient human remains. Others say that there is value for all in learning about human history.

What does it cost to sequence an ancient genome?

Costs can also range highly, depending on the quality of sample and level of sequence completeness required. A simple study might be as little as $10,000–$50,000 and an excellent whole genome a few hundreds of thousands.

Can ancient DNA influence modern disease?

Yes. Through examination of how ancient humans’ immune systems functioned, scientists can infer about resistance to disease. There are some old genes that served to protect us against infections which persist in people today.

The Road Ahead

New technologies have made ancient DNA a reality rather than a fantasy, and powerful scientific tool. What had previously been a process that took years and millions of dollars could soon take weeks and cost thousands. Researchers went from laboring to sequence a few hundred DNA letters at the time to simply reading off billions of As, C’s, G’s and T’s.

We’re in a golden age of ancient DNA. Each year, new discoveries force us to reconsider the past. We have learned that Neanderthals were our kin, not our supplanters. We have found human species we never knew were there. We’ve watched evolution occur in real-time by comparing the genomes of ancient and modern organisms.

The surprises won’t stop coming over the next ten years. With advances in technology and even lower costs, thousands more ancient genomes will be sequenced by scientists. We will know how animals and plants reacted to climate changes in the past. We’ll follow the beginnings of agriculture and then domestication. We could even begin to work toward resurrecting extinct species.

DNA is the script that runs the show of life on Earth, and increasingly, technology is allowing us to read it. Ancient genes speak to us over thousands of years, and we are only starting to hear what they have to say. And the secrets they preserve about our past will enable us to meet the challenges of the future.

Each scrap of ancient DNA is a message from the past — one that has waited thousands of years for us to develop the technology to read it. Thanks to smart scientists and some amazing machines, we’re just now starting to open those messages and they are telling us the story of life — a story that turns out to be even more amazing than we ever thought.

Have you ever been curious why your stomach feels jittery before a big presentation? Or why some folks thrive on taking risks and others play it safe? The solution could rest in our evolutionary history, reaching back tens of thousands of years to the time when our ancestors lived in small bands, hunted for sustenance and confronted the kind of challenges that are very different from those we face now.

It is not only that opposable thumbs and two legs evolved. It’s believed to have also influenced many of the behaviors, emotions and social dynamics we observe in humans today. But does evolution actually account for why you procrastinate on your homework, why social media seems so addictive or why people fall in love? This article examines the tantalizing link between our ancient history and current behaviors, and asks what evolution can tell us — and cannot tell us — about how we live now.

What’s Evolution Got To Do With Behavior?

Evolution is the way that living things change over time, over many generations. Traits that enhance the ability of an organism to survive and reproduce tend to be common in a population over time. This rule doesn’t just work for physical traits such as sharp teeth or camouflage patterns. Now scientists know that behaviors can evolve, too.

Our ancestors who made smart decisions — say, working well with others, staying away from dangerous predators, finding worthwhile foods to eat — were far more likely than our forebears who didn’t to stay alive long enough to have children. Over many generations the psychological mechanisms that led to these successful responses became ingrained as aspects of human nature. This discipline is called evolutionary psychology, and it seeks to explain how natural selection designed the human mind.

Here’s one way to think about it: your brain is a smartphone that still runs some extremely outdated apps. That software was created for a planet that had no cities, no schools and not even the internet. This tendency of ours manifests in a host of both endearing and afflictive ways, from an irrational fear at the prospect of public speaking to making mountains out of molehills over our favored political candidate’s prospective victory. Many such automatic reactions and feelings made good sense 50,000 years ago but now seem downright weird or troubling in contemporary life.

The Old Brain in the New World

To see how evolution affects behavior we must realize that more than 95% of these years were spent as hunter-gatherers. Our ancestors lived in small bands of between 25 and 150 people, moved constantly to find new sources of food and frequently confronted predators, starvation and rival groups.

The human brain is adapted to solving problems that were vital for survival in this environment. Natural selection was selective for those who could:

• Spot threats fast and respond with fear or aggression
• Form tight bonds with group members for survival
• Remember water and food sources
• Read faces and social cues
• Status competition within the group is also a factor
• Settle for healthy mates that could potentially bear offspring

These were literally matters of life and death skills. Those who didn’t have it were less likely to live long enough to reproduce. Today, we’ve inherited these psychological functions, despite the fact that the world has radically changed.

Why We Crave Sugar and Fear Snakes

Some modern behaviors are perfectly logical from an evolutionary perspective. Consider our love of sugar and fatty foods. In the ancestral era, calories were scarce and difficult to get. Fruits, honey and fatty meats offered concentrated energy that might be the difference between life or death from starvation. Those people with a hankering for these foods and those who ate as much of them as possible when they were available had an edge in survival.

Fast forward to the present, and that same need creates issues. We are awash in cheap, calorie-dense snacks, but the primitive wiring in our brains still behaves as if we might not eat again for days. This mismatch between what we’ve evolved to prefer and our modern environment is one contributor to the obesity epidemic.

The same goes for the fear of snakes and spiders. Even people who have never lived in cities populated by dangerous animals often possess instinctive fear reactions to such creatures. Meanwhile, we don’t have a reflexive terror of the genuinely deadly modern dangers in our midst — cars, electrified outlets. Why? Since snakes and spiders were serious threats for humans throughout their evolutionary history, while cars have been around as a danger only for about 130 years — not nearly long enough to evolve our own built-in fear response.

Social Behavior: Why Reputation Is So Important

Humans are incredibly social, and evolution has a lot to say about why we do the things we do with each other. Your reputation was life and death in tiny ancestral groups. And if other members of the group perceived you as selfish, unreliable or untrustworthy, you might get excluded from it — a sentence close to death.

This may be why we care so much about what others think of us. That moment of total embarrassment after you’ve botched something in public? That’s your brain wanting you to keep up social appearances. The satisfaction that comes from someone commending your work? That is a reward for behavior that enhances your reputation.

Gossip is a similarly ingrained behavior, from an evolutionary perspective. In ancestral environments, information about who could be trusted, who was a good hunter or who was cheating on their partner could be extremely valuable. Those groups that communicated well could make better decisions about when to cooperate and punish each other. Today, the role of gossip seems to be roughly the same, even if we feel more guilty about participating in it.

Evolutionary Mismatches in Contemporary Living

Prehistoric Environment	Evolved Response	Contemporary Environment	Effect
Calorie scarcity	Crave sugar/fat	Addictive junk food	Obesity, diabetes
Tribal threats	Fear outgroup	Large nation states	Racial tension
Rare public speaking	Stage fright	Diverse audiences	Panic attacks
Face-to-face interaction	Seek approval	Anonymous online spaces	Cyber-harassment
Limited information	Crave novelty	Social media feeds	Information overload
Real physical threats	Animal alarm system	Minor daily stressors	Chronic anxiety

Love, Attraction, and Choosing Partners

Evolution has especially powerful accounts of romantic behavior. Prior to modern society, selecting the perfect mate was among a person’s most critical decisions. Your decision affected not only your happiness but also your survival, as well as the success of your children.

Men and women appear to have evolved less similar mate preferences, indicating that waves of reproductive challenges shaped the sex-specific priorities. Women, who invest more in pregnancy and child-rearing biologically, are also more inclined towards partners that exhibit signs of being able to provide resources and protection. Men, for whom offspring are potentially less individually costly than for women, generally reveal more interest in clues linked to reproductive capacity.

That is not to say that these preferences dictate all of our choices — the culture we are raised in, our individual personalities and personal experiences play a huge role. But evolutionary psychologists say these basic instincts still do in fact push people toward one another in culturally uniform ways.

The strong emotions of romantic love — the butterflies, the obsessive thinking and even risky behavior that result from it — all also make evolutionary sense. These emotions inspired our ancestors to pair up in bonds that allowed them to raise children successfully despite our taxing environment.

Aggression, Competition, and Status-Seeking

The gain from having status within the group has been real, throughout human evolution. Higher status brought better food, more desirable mates and more allies for protection. This led to powerful evolutionary pressure to struggle for status and to care deeply if not obsessively about our rank in comparison with others.

We see those tendencies everywhere today. Students compete for grades, athletes compete for championships, businesses compete for customers and people compete frantically to gain followers on social media. The competitions themselves may differ, but the underlying spirit is the same.

Young men are significantly more likely to take risks and compete than women. Evolutionarily, it makes sense. In the environment of evolutionary adaptedness, men who took risks and competed effectively would have had a large impact on their reproductive success. Playing it safe wasn’t always beneficial.

This doesn’t give a free pass to harmful aggressive behavior — understanding the evolutionary roots of some behavior isn’t the same as saying it’s OK or unchangeable. But it does help explain why certain patterns show up again and again in diverse cultures and historical periods.

Cooperation and Altruism: The Puzzle of Helping Others

One of the behaviors that stumped evolutionary scientists at first was altruism, helping others in ways that might be costly to yourself. If evolution is about survival and reproduction, why do we sacrifice for others?

Several evolutionary mechanisms that explain cooperation have been discovered by scientists:

Kin Selection: We’re more apt to assist family members because relatives contain our genes. By helping a brother or cousin to survive, your genetic family also gets through, even if you don’t get reproductive success.

Reciprocal Altruism: “You do me a favor, I’ll do you one back.” Assisting someone who might have the chance of returning the favor in the future is a sound survival strategy. Those of our ancestors who worked well together were successful, and the pure freeloaders among them could be detected and excluded.

Reputation and Indirect Reciprocity: It may well pay to help strangers, if being helpful earns you a good reputation as a known generous person. All members of small ancestral groups would have known one another’s behavior. People were drawn to help those with good reputations.

Group Selection: Cooperative groups could out-compete groups of defectors. This exerted pressure toward pro-social behaviors that were beneficial for everyone overall.

It’s why humans can be extraordinarily generous and cooperative, while still indulging in no shortage of competition with one another.

What Evolution Cannot Explain

Though evolution can give us some incredible insights into human nature, it’s also key to remember its limitations. Not all behaviors have obvious evolutionary explanations. Some important points to remember:

Culture matters enormously. Humans learn from their societies and cultural evolution occurs orders of magnitude faster than genetic evolution. The particular languages we speak, the food we eat and so much else — far from being reducible to evolutionary considerations, these can be worlds away between cultures.

Individual differences are real. Evolution accounts for general tendencies in human psychology, not why exactly you chose your major or what movie you have a crush on. We are all products of our personal experiences, relationships and choices.

Modern behaviors aren’t always adaptations. Some of what we do is a side effect of adaptations meant to serve other functions. For instance, we weren’t selected for the capacity to read — writing was invented just 5,000 years ago. Instead, reading co-opts brain systems that evolved for other purposes — such as identifying objects and processing language.

Evolution doesn’t render behaviors inevitable or cast them in stone. Knowing the evolutionary origins of a behavior is not the same as being slaves to our genes. Humans are incredibly malleable, and can override evolution with conscious effort, the support of friends and family, and cultural practices.

The Controversial Side of Evolutionary Psychology

Evolutionary accounts of human behavior are highly contentious and the critics have some good points. There is some fear that evolutionary psychology can be appropriated to justify inequality or harmful behaviors by claiming they’re “natural.” This is a dangerous manipulation of the science — and what’s natural isn’t always good or right.

Others have criticized evolutionary psychology for producing “just so stories” — explanations that may sound reasonable but are difficult to test scientifically. We certainly can’t time travel to see our ancestors or conduct experiments on hunter-gatherer societies, after all.

Another worry is that it may be an oversimplification of complex behaviors. Human behavior reflects the interplay of genes, development, culture and individual experience. If we focus too strongly on evolution, we are likely to overlook these other essential elements.

However valid these criticisms, most scientists also believe that the theory of evolution has had an impact on human psychology. The trick will be to do evolutionary thinking well and combine it with the insights of other fields, from anthropology and sociology to neuroscience. For a deeper dive into the science of evolutionary psychology, explore additional research on how evolution shapes the mind.

Practical Applications: Using Evolutionary Insights

It’s not just academically interesting to know what the evolutionary roots of behavior are — it has practical applications. Here are some examples:

Health & Nutrition: Understanding that we’ve evolved to seek out calorie-dense foods can guide the best weight loss strategies. We don’t have to depend on willpower alone; we can alter our environments so they better foster healthy decisions.

Education: Knowing that children’s brains evolved to learn through play, storytelling and apprenticeship — not sitting in rows listening to lectures — can help us design more effective systems of education.

Mental Health: The mismatch between our evolved psychology and modern environments may be responsible for much anxiety and mood disorders. This view may help to diminish stigma and imply novel treatments.

Workplace Design: Appreciating that humans need to be connected with others, long for status and crave a sense of meaningfulness in their work can help organizations design more satisfying workplaces.

Technology Design: Knowing both what inspires human attention and why it does so can allow us to design technology which acts according to our real interests not by exploiting our psychological weaknesses.

Sources of Human Behavior

Human Behavior = Evolutionary Adaptations (40%) + Cultural Learning (30%) + Individual Experience (20%) + Current Environment (10%)

Note: These percentages are illustrative and can vary dramatically depending on the particular behavior. The critical point is that they all interact to cause behavior.

The Future of Human Behavior

One interesting question is whether human behavior is going to be further shaped by evolution. In one sense, yes — evolution never stops, so long as some members of the population have more children than others. But natural selection is a glacial process, and modern medicine and technology have mitigated many of the timeless survival pressures that once could be counted on to shape our species.

Some scientists conjecture how modern environments could be influencing future evolution. For instance, if people who need less sleep seize more hours at work and making money, could the genes that support shorter sleep spread? If social anxiety undermines peoples’ dating success, could the humans of tomorrow grow less introverted?

These scenarios remain speculative. In reality, cultural and technological shifts take place much more quickly than genetic evolution does, so they are likely to have far greater influence on the direction of future human behavior.

Frequently Asked Questions

Can evolution explain mental illness?

Evolutionary views illuminate certain mental health problems. For instance, anxiety disorders could be connected to an overactive threat detection system designed for life in ancestral environments. Depression could be associated with an evolved response to loss or low social status. But mental illnesses are complex disorders with many causes, and evolutionary explanations represent only part of the picture. They shouldn’t be invoked to stigmatize or assume that mental illness is somehow “natural” and should not be medically treated.

Is behavior predetermined by evolution?

No. Evolution shapes behavioral predispositions and preferences, but it does not dictate specific behavior. We are endowed with free will and conscious control over our choices, and can override evolutionary imperatives. Behavior is also influenced by culture, education and one’s own values in addition to evolutionary impact. Human beings are incredibly flexible, adaptable creatures.

If evolution shaped our behavior, why do people in different cultures act so differently?

General psychological mechanisms and tendencies were created in the course of evolution that are universal in the human species, but manifest themselves differently because of cultural variation. Think of it as a recipe that takes local ingredients — the basic structure is the same, but the resultant dish changes. Culture is what fills in the form predetermined by our biological equipment.

Can we predict how someone will act if you place them in a certain setting?

Not with precision. Evolutionary psychology accounts for statistical tendencies in large populations, not individual actions. There are many considerations that determine what any given person does in a particular situation. But these evolutionary insights can provide insight into why some behaviors are popular and what psychological mechanisms make them possible.

Is evolutionary psychology sexist or an excuse for inequality?

Some have improperly used evolutionary concepts to defend their exploitation and abuse of others, but that is an inappropriate application of the science. Evolutionary psychology explains how behaviors came to be; it doesn’t prescribe how a society should structure itself. The recognition of evolved differences isn’t to say one group is better than the other, nor does it mean that contemporary social hierarchies necessarily are either inevitable or desirable. Good evolutionary science is descriptive, not prescriptive.

Bringing It All Together

So does evolution explain modern human behavior? The answer is yes and no: Evolution does offer important clues about why we have the psychological predispositions, emotional responses and social structures that we do. A great many otherwise mysterious things about human beings make perfect sense once we view them through an evolutionary lens.

But it’s only one piece of a very big puzzle. Culture is important, as are personal experiences, development and current conditions that influence behavior. We are not automatons playing out programs written in our genes; we are flexible, creative beings with the power to reflect on our urges and make choices with our wonderful brains.

Knowing the evolutionary roots of behavioral proclivities doesn’t excuse bad behavior nor make change impossible. Instead it affords us valuable insight into our own psychology. When we know why we’re pulled toward junk foods, or why we care so much about social standing, or why we tend toward tribalism with outsiders, then we can make informed decisions on how to design a more thoughtful world that brings out the best in us.

The human mind is a remarkable thing, honed over millions of years of evolution, and yet living in a world our ancestors wouldn’t even recognize. We haul ancient instincts into modernity, occasionally fitfully adapting to the mismatch but also taking advantage of our evolved abilities for creativity, cooperation and problem-solving to develop astonishing civilizations. It is this mix of the old and new, instinct and reason, that makes human behavior infinitely interesting to study and understand.

Evolution is not just some musty old textbook subject — it’s a living, breathing science that continues to amaze us. For 150 years Charles Darwin’s theory of natural selection has been the bedrock for how we think about life on Earth. But contemporary scientists are finding out that evolution is even more complicated, cool and bizarre than anyone knew.

With recent advances in genetics, paleontology and molecular biology, researchers are being forced to reconsider some long-held thinking about how species change over time. Other findings contradict or totally revolutionize the prevailing “survival of the fittest” story. These are not minor tweaks of existing ideas; they are game changers that transform our entire conception of life’s history.

In this piece, we are going to look at seven amazing scientific studies that have revolutionized one’s thinking about how evolution works. From rogue bacteria defying the rules of inheritance to birds that evolved twice, these discoveries show just how much weirder and more wonderful evolution is than we ever could have imagined. Prepare to see the natural world through an entirely new lens.

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The Revelation That Genes Aren’t Everything

For years scientists have believed that evolution occurs when patches of DNA are copied and expressed in an organism’s offspring without being altered, allowing for the chance that new traits favored by natural selection might eventuate. If you wanted to know how a species evolved, all you had to do was gaze into its genes, no? Wrong. Thanks to a cutting-edge science called epigenetics, that assumption is being blown out of the water.

What Epigenetics Revealed

It was a group of researchers at the University of Cambridge who conducted a study of water fleas that blew all its predecessors out of the water. What they found was that environmental stress — from predators and other challenges — could bring on changes in gene expression that were inherited by the next generation, even when the DNA sequence itself hadn’t changed. It’s a bit like somebody scribbling notes in the margin of a book, never altering what’s on the page.

This would mean that organisms can inherit characteristics their parents acquired in the course of their lifetime, which sounds suspiciously like Jean-Baptiste Lamarck’s old theory that scientists dismissed 200 years ago. But here’s the catch: Epigenetic modifications don’t actually rewrite a person’s genetic code — they just determine which genes are activated or silenced. It is like owning a huge playlist of songs, only you get to skip tracks without eliminating them.

Why This Matters for Evolution

With epigenetic inheritance comes a whole new dimension of evolutionary change. Organisms can evolve in response to selective pressures far more rapidly than by conventional genetic mechanisms. If instead, a population encounters a sudden drought, perhaps epigenetic shifts could permit them to adapt within a literal lifetime rather than banking on tens of thousands of years for the exact mutation that would help.

This discovery has massive implications. It means that evolution is not just about random mutations and natural selection — it’s also about how organisms actively respond to their environment and transmit those responses to the next generation. The process of evolution has suddenly appeared to be a good deal more dynamic and flexible than the slow, grinding change we heard about in school.

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When Bacteria Swap Genes Like Baseball Cards

If you assumed that genes can pass only from parent to child, think again. Scientists who study bacteria have found something called horizontal gene transfer, and it’s completely nutso.

How Bacteria Break the Rules

“Orthodox evolution,” as Albert questions this old view, takes a straightforward form: genes travel up and down between parents and offspring. But bacteria do not play by those rules. In fact they can literally exchange genes with utterly unrelated bacteria, even from different species. It would be like if you could all of a sudden train yourself to breathe under water by shacking up with a fish for an excessive amount of time.

One groundbreaking study in Science traced the spread of antibiotic resistance among populations of bacteria. The scientists discovered that genes for resistance spread rapidly between entirely different species of bacteria, potentially in as little as a matter of hours. In a single bacterium, immunity to an antibiotic is borne, then that genetic resistance is circulated like notes in class.

The Evolutionary Game-Changer

This finding totally turns our idea of how evolution works in bacteria on its head. “If you picture a nice clean tree of life rooted in some primeval node, where everything is interacting through descent and the movement of genetic material,” Ms. Adam said, “it’s really a whole bunch of knots.”

It is horizontal gene transfer that enables bacteria to become frighteningly antibiotic resistant so quickly. It’s not the story of a single species gradually mutating — it’s the story of an entire microbial community passing around survival strategies, like some sort of underground network. (For medicine, agriculture and our understanding of how life first evolved, the implications are enormous.)

Type of Gene Transfer	Traditional Inheritance	Horizontal Transfer
Direction	One generation to next	Unrelated organisms
Speed	Generational	Hours or days
Distribution	All complex life	Most prevalent in bacteria
Evolutionary Effect	Slow, gradual change	Rapid evolution

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Evolution Doesn’t Always Move Forward

This is going to mess with your head, but sometimes evolution runs in reverse. A study on fish dwelling in caves found that evolution can even erase traits that took millions of years to develop.

The Blind Fish Mystery

The Mexican blind cavefish are the epitome of regressive evolution. These fish descended from perfectly normal, fully sighted ancestors, but generations of life in pitch-black caves caused their eyes to vanish entirely. University of Maryland researchers even studied their DNA, and found something astonishing: the genes for eyes are there – but turned off.

And why the hell would evolution get rid of something like eyes? The answer is surprisingly practical. Eyes use a ton of energy to be built and maintained. In a place where seeing provides no benefit, that energy could be better applied elsewhere—to building a more sensitive lateral line system that detects vibrations in the water.

Rethinking Progress in Evolution

This discovery goes against the commonly held idea that evolution constantly leads to more complex or “better” organisms. Losing characteristics can remain the smartest evolutionary moves. It’s not about becoming “better”—it’s about becoming better suited to your environment at the moment.

Such regressive evolution occurs more frequently than one might suspect. Whales lost their rear legs, snakes lost their limbs and many island birds became flightless. Each loss is an evolutionary benefit in a given scenario. There’s no aiming or assisting in evolution — it’s all about survival and procreation wherever you find yourself living.

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The Species That Evolved Twice

Evolution is meant to be a one-way street. When a species goes extinct, it’s gone forever, isn’t it? One of the most bizarre evolutionary oddities ever documented has to do with rails (the type of bird) from the Indian Ocean island of Aldabra— and it suggests that survival is completely optional.

The Rails That Just Wouldn’t Die

Rails are flightless birds that repeatedly colonized Aldabra island over thousands of years. Here’s where it gets weird: The island was submerged under water in a huge flooding event about 136,000 years ago that drowned out everything living there, including the flightless rails.

But once the island rose again, Madagascar’s rails colonized it anew. And here’s the kicker — they turned into flightless birds once more and with eerily similar features to the already extinct ones. They studied fossils before and after the flooding, and found that both lineages evolved incredibly similar physical characteristics: reduced wing bones and stronger leg architecture.

What Iterative Evolution Means

This phenomenon, known as iterative evolution, reveals that under the right conditions, evolution can be surprisingly predictable. Put the same species in the same environment, and maybe it evolves the same way twice. It’s as if you’re rewinding the tape of life and playing it again.

This finding implies that evolution is not as random as we previously believed. The pressures of environment can be so strong that it forces evolution down the same lines, at different times. It’s a little like the way different societies invented the wheel independently — some solutions are so well suited for certain problems that they crop up over and over.

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Your Immune System Evolves as You Age

When we think of evolution, we tend to visualize changes occurring over many generations. But what if in just one human lifetime, evolution could potentially sway a population from being rundown by disease to being well? Immune system studies show that the process of Darwinian evolution is occurring currently within your body.

The Evolution Happening Inside You

In the process of defending your body against infections, your immune system employs a trick called somatic hypermutation. As it turns out, and considering that this editor is not a scientist myself, when one of these new pathogens invades your body, immune cells immediately begin to produce millions of similar — but slightly different — versions of antibodies. The best-fitting antibodies against the invader proliferate, while the less effective ones die off. Sound familiar? It’s natural selection on a warp-speed clip inside your body.

One study in Nature Immunology followed how B cells, a type of immune cell, change to fight HIV. Scientists witnessed the evolution of antibodies as they mutated, becoming better at neutralizing the virus. Some antibodies cycled through dozens of “generations” of evolution in only a small number of months, gaining helpful mutations at a pace that would take an entire organism millions of years.

Evolution on Fast-Forward

This finding suggests that evolutionary principles work across other scales — not just over millennia for species, but within a single organism over months or days — and could even contribute to differing human disease risks. Your immune system, in essence, is an evolutionary laboratory that runs millions of experiments at once to find the best solution to each new threat.

Knowledge of this process has transformed the field of vaccine science and immunotherapy. By learning how antibodies evolve naturally, scientists can create more effective vaccines and treatments for diseases like cancer and HIV. Evolution isn’t just ancient history — it’s happening right now, in every living thing.

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The Virus in the Back of Our Minds

Here’s something that might blow your mind: About 8 percent of your DNA is viral. Seriously. Not only is this viral genetic material not rubbish, it has been an important player in human invention.

How Viral DNA Shaped Humanity

Millions of years ago, the sperm or egg cells of our ancestors were infiltrated by viruslike entities known as retroviruses, which wove their DNA into ours. Those viral genes became a part of the human genome, incorporated into DNA that continued to be passed down from generation to generation. For years, scientists believed these sequences were just useless baggage — evolutionary remnants with no function.

But a new study published in Cell showed that some of these very same viral genes are actually necessary for human existence. One of the viral genes helps build the placenta, which is the organ that feeds growing babies in the womb. Without this vestige of ancient viral DNA, we could never be born as the humans that exist today.

Viruses as Evolution’s Secret Weapon

This finding turned scientists’ understanding of the viral role in evolution upside down. Viruses are not just disease-causing entities that can prompt pandemics and other threats, they’re also drivers of innovative evolutionary designs. By shuffling around genes among various organisms, viruses have sped up evolution and developed entirely new biological features that never would have arisen through just normal mutations alone.

The implications are mind-blowing. Viral DNA has shaped the evolution of not just our brain and immune system but also, as some scientists now say, of we humans themselves. Parts of what we think of as fundamentally “human” are in fact the legacy of ancient viral infections. Evolution is not merely a world of competition and survival of the fittest, but also one of cooperation, integration with other life forms (including viruses), flexibility and mutual dependence.

Learn more about how viruses have shaped human evolution from Nature.

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Evolution in Action: A Case of Superfast Evolution

So evolution is meant to happen over millions of years, isn’t it? Which is what makes a study of lizards on the Bahamas so special — researchers observed evolution happen in just under a year.

The Hurricane That Proved Darwin Right

In 2017, researchers from Harvard University were studying anole lizards on a number of small Caribbean islands just as Hurricane Irma struck. The category 5 storm was quite the catastrophe, but it also caused a natural experiment. After the hurricane had come and gone, researchers found that the surviving lizards exhibited traits distinct from those of the pre-storm population.

These survivors had larger toe pads and longer front legs — features that would have helped them stick to branches in high winds. The lizards that did not possess these traits were actually blown away by the storm. The average characteristics of the population had changed noticeably in one generation. Natural selection had occurred in the blink of an eye, right before the eyes of the scientists.

What Rapid Evolution Teaches Us

This study is a blow to the notion that evolution proceeds slowly and gradually. Populations can evolve massively in just a few generations when environmental pressures are intense. To be clear, it’s not as if the lizards magically evolved bigger toe pads during the storm — the genetic variation was already there in that population. The hurricane only decided which variants made it through to spread their genes.

This fast pace matters for how species might respond to climate change. As habitats change more rapidly than ever, some species may be able to adapt fast enough to survive. Others won’t be so lucky. The factors that enable rapid evolution may be crucial for conservation efforts and predicting which species will make it through to the end of the next century.

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The Future Implications of These Findings

These seven are only a small sampling of the groundbreaking work being done to rewrite evolutionary biology. Taken together, they offer a picture of evolution that is far more intricate and active — and interesting — than the one we learned in school.

Evolution isn’t a one-way, steady march toward progress. We’re flexible, too: We swap genes and we respond to the environment (even by integrating retroviruses into our own genome), adapting quickly when running forward won’t serve, even doing it backward when that’s called for. It works at many scales at once — from cells battling infections inside your body to species evolving over millions of years.

The Bigger Picture

What makes these discoveries so exciting isn’t only that they are neat science facts (which, of course, they are). And they are put to use in the real world, shaping our daily lives. Studying epigenetics enables us to see how environment can impact health from one generation to the next. Understanding horizontal gene transfer describes antibiotic resistance, and informs medical interventions. Knowing that evolution can happen quickly would allow scientists to predict how species might respond to something like climate change.

Most crucially, these studies serve as a reminder that science isn’t a static canon of knowledge — it’s an ongoing conversation. Every answer raises new questions. Every discovery opens new doors. The history of the evolution of evolutionary theory reads like an example of evolution in itself: consistently changing and adjusting to new information.

Where Do We Go From Here?

The potential of evolutionary research is exhilaratingly so. Thanks to technological advances, scientists can observe evolution in action, watch genetic changes sweep through populations and see mechanisms Darwin never could have dreamed of. We are creating the tools to not just witness evolution, but perhaps influence it in beneficial directions — though that comes with ethical qualms we’re just beginning to sort out.

These seven studies demonstrate that we’re in a golden age of evolutionary biology. The next game-changing find might be around the corner, and could rewrite our understanding of things anew. And that’s the magic of science: It is never done surprising us.

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Frequently Asked Questions

What is the biggest challenge to modern evolutionary theory?

The most likely game-changer is the discovery of epigenetic inheritance. It reveals that organisms can transmit traits to their offspring other than by adding or deleting genes, because of changes created by problem-solving or general organismal demand during the life cycle that are stored in some kind of information inherited from the parent’s germline. (This could include proteins, RNA molecules and chemical changes to DNA.) It makes evolution operate far faster — with a system Wallace called “the first step toward Lamarckism”— than via waiting for new mutations in germ cells changing the sequence of A’s, T’s, C’s and G’s.

Can evolution really be that quick, as these studies propose?

Absolutely. Although some evolutionary changes require millions of years, others occur after just a few generations when the environmental pressure is strong enough. The lizard hurricane experiment showed that measurable evolution can take place in a year.

Are humans capable of horizontal gene transfer?

Not the way it does in bacteria. Humans and other complex organisms do not share genes with unrelated species over the course of their lifetime. But we did take up viral DNA from ancient infections, and those sequences have become integrated in our genome.

Are these findings controversial in the scientific world?

Not particularly. These results have been published in peer-review journals and are uniformly held by the scientific community. They do not upend evolution — they deepen and enhance our understanding of how it works.

How do genetic mutations differ from epigenetic changes?

This is the moment when genetic mutations rewrite the sequence of DNA just as if they had edited words in a sentence. Epigenetic modifications don’t change the words themselves; they simply determine what gets emphasized or de-emphasized in a given context — sort of like underlining different sentences using the same words.

What does this mean for the teaching of evolution in schools?

These findings also indicate that evolutionary education should be broader than natural selection and mutation. The students need to understand concepts such as epigenetics, horizontal gene transfer and the various mechanisms for evolutionary change. The tale is trickier but also more interesting than the simpler one.

Would humans evolve that quickly, as did the lizards in the hurricane study?

In principle, yes, but human generation times are far longer than those of lizards so it takes awhile. Also, advanced medicines and technology often counteract the selective pressure for change (which would otherwise lead to faster evolution). But our immune systems also evolve quickly over the course of our own lifetimes — in response to new diseases.

Have you ever scanned your family members and noticed that you have your dad’s nose, or Mom’s eyes? That’s DNA at work. But DNA is revealing much more than just who we resemble. It’s more like a great big history book encrypted in microscopic code, which tells us where humans originate from, how we are all connected and what makes us different from other living beings. In the decades since, scientists have pored over this biological instruction manual — and what they’ve found inside is mind-boggling.

Each of us, each living person carries antiquity in their cells. These stories stretch back hundreds of thousands of years, all the way to our ancient human forebears who roamed Africa, weathered ice ages and populated nearly every inch of the globe. Insights from DNA, the story of humanity’s incredible journey across the planet is being rewritten — and none of us are quite who we thought.

What DNA Tests Really Tell Us About Our Ancestors

DNA is kind of like a recipe book that has gone through generations and generations. Your parents gave each of those halves a boost. This process has been underway since the first humans walked on this planet. But here’s the cool part: DNA doesn’t copy itself perfectly. These are tiny changes, or mutations that occur over time. Those mutations serve as bookmarks in history — they can help scientists understand when distinct groups of people separated from one another and where they went.

Put another way: if you and your cousin both have copies of Grandma’s cookie recipe, but each make slight adjustments over the years, someone analyzing those recipes could determine that they must have come from the same original source. DNA operates similarly, only in this case instead of cookies I’m referring to the blueprint for assembling a human being.

These small differences can be seen by researchers when comparing the DNA of people living in different regions of the world. The more differences there are between the DNA of two people, the longer time has passed since their ancestor split into separate lineages. The fewer the differences, the more recently they branched from a common ancestor. This approach has transformed the way we think about human history.

Africa: Birthplace of the Human Story

Go back about 300,000 years and everyone on the planet is African. Yes, you read that correctly — the ancestors of every human being on earth originated in Africa. This is not some airy-fairy idea — scientists have actually shown this based on DNA that they’ve looked at from people all over the world.

The evidence is overwhelming. All the time that scientists compare their material between these various populations, African pops have always had the greatest genetic diversity. What does this mean? That’s because human beings have been living in Africa for longer than they’ve been anywhere else, and there has therefore always been more time for genetic variations to accumulate. The groups that left Africa and spread to other continents have lower diversity because they are descended from smaller bands of people who brought only a fraction of the total variation found in their African ancestors.

One of the most famous lines of evidence involves mitochondrial DNA, which is transmitted from mothers to their children. Following this maternal line back across generations led scientists to what they’ve labeled “Mitochondrial Eve” — not the first woman, but the most recent common female ancestor of every living human. She dwelled at a place in Africa somewhere between 150,000 and 200,000 years ago.

Similarly, analyzing Y-chromosome DNA (handed down from fathers to sons), they tracked down “Y-Chromosomal Adam,” who also lived in Africa at roughly the same time. These conclusions are fairly straightforward: Modern humans first arose in Africa, and from there spread elsewhere.

The Great Human Migration: Why People Spread All Over the Earth

Then something extraordinary happened about 70,000 to 100,000 years ago. Thousands of years ago, groups of humans left Africa and spread out across continent after continent. This wasn’t a single-headed rush for the exits, but rather waves of migration that took place over several thousand years. DNA evidence has allowed scientists to map these ancient journeys in remarkable detail.

The Path Out of Africa

The first migrants probably swept across from northeastern Africa into the Middle East and western Asia. From that single cellar, some groups went east toward Asia and west to Europe. DNA markers serve as breadcrumbs along these ancient trails, pointing toward the routes our ancestors traveled.

Here’s an oversimplified timeline according to genetics:

Era	Event	Migration	DNA Evidence
70,000-100,000 years ago	First groups leave Africa via Middle East		Common genetic markers in Middle Eastern and African populations
50,000-60,000 years ago	Populations reach South Asia and Australia		Unique mutations found in Aboriginal Australian DNA
40,000-45,000 years ago	Arrival of humans to Europe		Genetic imprints on Europeans different from those on Asians
20,000-30,000 years ago	Rapid migration into East Asia		Genetic markers sweep across Asian populations
15,000-20,000 years ago	First human crossings into the Americas		Native American DNA linked to Siberian lineage

All of these movements left genetic footprints that scientists can use to detect them to this day. For instance, Native Americans have certain DNA markers that directly trace them to populations in Siberia, showing that their forebears moved across a land bridge connecting Asia and North America.

Meeting Other Human Species: A DNA Surprise

Now here’s where the story really starts to throw sparks. For much of the past 150 years, scientists believed anatomically modern humans (Homo sapiens) didn’t mix with other human species. We thought that as our ancestors moved out, they simply replaced the other human-like species they encountered, such as Neanderthals in Europe and Denisovans in Asia.

DNA evidence showed that idea to be totally wrong.

In 2010, researchers were able to sequence the Neanderthal genome — the full set of DNA from these long-dead human cousins. When they compared it to the DNA of modern humans, they found something amazing: Many of today’s people have some Neanderthal DNA! If you have ancestors who once lived outside of Africa, then likely, your genome contains around 1-2% Neanderthal DNA.

That’s to say, when modern humans began moving into Europe and Asia 60,000 years or so ago, they weren’t just replacing Neanderthals — they were also interbreeding with them. Such intermixed relationships played out tens of thousands of years ago, and these Neanderthal genes spread down through so many generations until they came to you.

What Has Neanderthal DNA Done for Us?

Certain Neanderthal DNA has hung on because it was actually useful. Researchers have found that certain Neanderthal genes influence:

• Immune system (aid to fight diseases)
• Types of skin and hair (adaptation to climate)
• Pain tolerance and perception
• Sunlight response and vitamin D synthesis

In a similar pattern, Denisovan DNA (another extinct human cousin known only from DNA evidence) also is present in modern populations of Southeast Asia, Australia and the Pacific Islands. Some Tibetan populations even harbor a Denisovan gene variant that helps them to survive at high altitude, where oxygen is limited.

DNA Detective ‘Worked Hard’ to Find How Scientists Study Ancient Humans

You might ask how scientists can study DNA from people who died thousands and thousands of years ago. It may seem impossible, but technology has made it possible.

When archaeologists do turn up bones or teeth from bygone millennia, they can occasionally fish out tiny samples of DNA that have survived. They are monumentally fragile, usually damaged samples — but even scant amounts of genetic material can be amplified and sequenced using modern laboratory techniques.

The process involves:

Meticulous extraction: Drill or scrape into ancient bones or teeth to gather powder samples

Isolation of DNA: The process of extracting DNA using chemicals to remove it from other substances in the cell.

Sequencing: Fancy machines read the genetic code letter by letter

Computer analysis: Sophisticated software reassembles fragments and compares them to modern DNA databases

The oldest human DNA successfully recovered until now is about 400,000 years old, though most ancient DNA research has involved samples between 50,000 and 200,000 years old, when preservation conditions are more favorable.

It’s in Our Genes: Regional Adaptations

As humans migrated to various regions throughout the world, they encountered different environmental pressures. It now enables DNA to tell us how we adapted to these different circumstances through natural selection.

Adapting to Climate

Those who lived closer to the equator evolved high levels of melanin (the pigment that gives skin its color) in order to defend against intense UV radiation. Populations that migrated to northern latitudes, with a weaker sun, developed lighter skin (and thus less protection against sunlight) and sweat more effectively; the latter helps produce vitamin D with less sunlight.

Food and Digestion

Most Europeans and some African and Middle Eastern populations developed the ability to digest lactose (the sugar in milk) during adulthood. That genetic switch occurred only in the past 10,000 years or so, after humans started domesticating cattle and drinking milk. Most of the world’s population remains unable to do so after infancy, in a sign that their ancestors didn’t survive on dairy farming.

High-Altitude Living

Andean and Tibetan populations both have genetic adaptations that help them survive at high-altitude. Tibetans possess genes (some passed down from Denisovans) that influence how their bodies use oxygen. Andeans in South America evolved other genetic solutions to the same problem — a striking example of evolution finding multiple ways of getting the same job done.

Disease Resistance

Some populations possess less permissive genetic variants for diseases prevalent in their regions. Sickle cell trait (which can result in sickle cell disease when present from each parent) is one; however, the heterozygous state actually confers resistance to malaria. This feature prevails in areas with past habitual malaria.

What Separates Humans From Other Apes

We share 98-99% of our DNA with chimpanzees, our closest living primate relatives. One percent might seem like a whisker of variation, a trivial scattering of genetic crumbs, but all that separates us from the chimpanzee is tucked away in that small percentage.

Key genetic differences include:

Genes for Brain Development: Humans have mutations in genes that govern brain size and complexity. We have comparatively larger brains relative to body size than the other apes, and more complex interconnections between neurons in our brains.

FOXP2 Gene: Dubbed the “language gene,” this gene is responsible for speech and language. Humans have a version of the gene that is distinct from the chimpanzee copy in just two amino acid substitutions — but those changes seem to be crucial to our ability to produce complex speech.

Hand Dexterity: Changes in the genes that influence hand and finger control allowed us to make and use complex tools with a level of precision unmatched by other apes.

Slower Development: Humans develop at a slower pace than other primates. Genetic changes gave us a longer childhood, allowing for more time to learn complex skills and behaviors.

Genetic Diversity: Why We Are All Brothers and Sisters

Here’s one that may surprise you: Humans have less genetic diversity than many other species. If you compared the DNA of two chimpanzees from different parts of Africa, there would be more genetic difference between them than between any of us sharing one continent as humans.

Why? Because humans experienced a population “bottleneck.” At some indeterminate time in the past — maybe 70,000 years ago — something (maybe because of a volcanic eruption or a change in climate) compelled all human populations at the time to take a nosedive. The entire human population in the world might have dwindled down to only a few thousand people.

And that means everyone alive today is descended from a relatively small surviving group. We’re all a great deal closer kin to one another than you might assume. In fact, any two individuals sampled at random share approximately 99.9% of their DNA sequence. All of the human diversity that we see, in terms of different features, different skin colors, different heights… comes from only 0.1% genetic variation.

And this undermines an important message: something as scientifically pernicious as race doesn’t exist genetically. The physical variations that we can see are superficial adjustments to various ecological conditions. From a genetic standpoint, there’s no such thing as a pure racial group. Humans have been mixing and migrating for all of history, and we now have a tangled mess of genetic connections.

Ancient DNA Rewrites History Books

A few of these DNA revelations have overturned our previous understanding of history altogether.

The Peopling of the Americas: Scientists argued for decades over when and how humans first arrived in the Americas. DNA evidence now demonstrates that the majority of Native American ancestry is derived from a single group of migrants that separated from East Asians and crossed into Alaska via a land bridge over the Bering Strait, no more than 23,000 years ago. But, and this is recent research, human migration was not so simple and single-wave but rather multiple waves of people arrived at different times.

The Ghost Population: DNA analysis sometimes picks up the traces of so-called “ghost populations,” which are ancient human groups known exclusively by the DNA they left in the more recent ones. An example of such population is the mysterious group of humans that had intermingled with both Neanderthals and modern humans but had never had their own fossils discovered.

Indo-European Languages: The spread of related languages across both Europe and Asia had long puzzled linguists. DNA research demonstrated that, 5,000 years ago, there were large populations’ movements from the Eurasian steppes that carried both language and genes across the continent.

Your Personal DNA Connection to the Ancient Humans

Nowadays, many people can uncover at least some of the secrets of their genetic heritage owing to consumer DNA testing. Such tests can help you discover fascinating details about your ancestry and connect you to populations from around the world. Learn more about how genetic ancestry testing works and what it can reveal about your personal history. While the test’s results might be limited and not all-inclusive, they still offer regular individuals a unique way to see the ancestral past. Most people discover some unexpected genetic connections that allow us to form a better understanding of the complex and rich human history of the past.

The Future of the DNA Research in Human Origins

Yet the ancient DNA field continues advancing with great speed. Numerous new methods are being developed each year that can facilitate the genetic analysis and extraction from the contaminated and older samples.

For future research, other exciting research directions include:

AI and Machine Learning: Applying artificial intelligence to scour massive genetic datasets for patterns that humans might miss — which could in turn expose subtle population movements and interactions we haven’t yet uncovered.

High resolution complete ancient genomes: With ongoing technological developments, researchers are attaining higher quality complete genomes from ancient individuals enabling even more precise details about their lives, customs, health and their relationships.

Frequently Asked Questions About Human Origins and DNA

Could DNA tell us what ancient humans looked like?

Yes, to some extent. There are certain physical traits that scientists can predict from ancient DNA — among them, skin color, hair type and texture, eye color and perhaps even some aspects of the face. But looks are complicated and affected by many genes, so predictions can be imperfect.

Why is there such a surge of interest in African genetic diversity?

The highest genetic diversity is in Africa, where humans have been for the longest time. This diversity is a genetic treasure trove that can assist scientists in interpreting human evolution and may be valuable for medical research, they said, since rare genetic variants might provide hints about disease resistance or other characteristics.

Did all people really originate from one woman and man?

Not exactly. “Mitochondrial Eve” and “Y-Chromosomal Adam” were not the only people living in their time — they’re simply whose maternal and paternal lines ultimately lived on to the present generation. Many others lived alongside them, but their mitochondrial or Y-chromosome lineages died out over time.

How reliable is DNA testing for ancestry?

Commercial ancestry tests are generally useful for recent ancestry (up to a few hundred years) and continental level origin. Yet they have shortcomings in determining specific countries or ethnic groups, particularly the farther back you look. The results are only as good as the reference populations in the company’s database.

Might we recover DNA from even more ancient human species?

DNA breaks down over time, and preservation conditions make a world of difference. The oldest recovered hominin DNA to date is approximately 400,000 years old and was extracted from remains in Spain, which had been preserved under very cold conditions. Although we will probably never recover DNA older than that of a fringe group like Homo erectus (which lived more than 2 million years ago), this is because DNA just doesn’t last.

What is the single biggest mystery remaining about human origins?

Many mysteries remain! The precise reasons humans evolved such enormous brains, the nature of language and why only one human species survived are still subjects of debate among scientists, as are some of the major migrations. Almost any new finding along the DNA trail tends to raise as many questions as it answers.

Why This All Matters Today

Learning more about DNA and human origins is not just a matter of curiosity about the past — it has powerful implications for our present and future.

Medical Uses: Clues for battling disease come from diversity in DNA. By learning why some populations are immune to certain diseases, scientists may be able to create better treatments for everyone.

Confronting Prejudices: DNA technology confirms conclusively every human is of the same species with only superficial differences. It subverts racist ideas of distinct races that is premised on the myth.

Climate Change Insights: Taking a lesson from ancient people on how to cope with shifting climates can prepare us for the environmental challenges we face.

Understanding Human Behavior: If we know where we came from, perhaps it will tell us something about who we are and why human behavior may be what it is and think in terms that lead somewhere.

The Tale in All of Your Cells

DNA has opened up a totally novel window on human origins. We now know for sure that all of humanity shares common ancestors who lived in Africa, that human beings ranged across the globe in waves over tens of thousands of years, and that we interbred on several occasions with other species.

Every human being bears genetic echoes of those ancient journeys. Your body is a mosaic, and if you aim your sequencing lens at you, you might come into clearer focus. Your genome is a field of broken mosaic tiles — few genes are completely good or bad; the impact of each depends on time and place. It includes chunks from humans who survived ice ages, crossed trackless oceans, conquered mountains and learned to thrive in deserts, forests and the frozen tundras of the Arctic Circle.

This genetic narrative links all of humanity in an incredibly literal sense. We speak many languages, embrace many cultures and follow many traditions, but share as few as a couple of hundred generations of common love and commitment. We are all Africans, in the deepest sense of the words, for that’s where humanity began.

The march of technology will yield even wilder nuggets about human origins, without a doubt. But the basic story is redundant: that we are all one human family with a single origin and journey of transformation over time. This is a story that has been written in the most indelible ink possible — DNA; it’s found in every cell of your body.

Next time you hold your hands in front of your face, look at yourself in the mirror or gaze upon your family members, take note that you’re just taking a peek at the present. You’re staring at the end product of an unbroken line that goes back hundreds of thousands of years, right to the very first people who walked under African skies and dreamed of a horizon far beyond.

For most of human history, we could only speculate about how our ancestors lived. Old bones were studied, species were compared and the puzzle of where we came from was reconstructed. But now, genetics has provided us with a powerful new tool—and it’s revolutionizing everything we thought we knew about human evolution.

Consider DNA to be our memories recorded in a language we are just starting to understand. Every cell in your body is this book, and it chronicles the story not only of you but of every human who preceded you. This book too scientists have learned to read more finely in the past two decades. What they are discovering is shocking, thrilling and sometimes completely surprising.

The tale of human evolution is too simple-minded — even misleading. It’s messier, more interesting and a surprise-filled place. Several different human species — or possibly subspecies of a single human type — lived at the same time. They fell in love, had children and passed on their genes in ways we never dreamt of. Some of us became suited to high mountains; others, cold conditions and helpful genes from species that aren’t quite human anymore.

This article will lead you through the newest findings in genetics and take on argument that is subverting centuries of deeply held beliefs: that tens of thousands of years ago, a group of peoples sallied forth from Africa to spread their genes everywhere, all but obliterating earlier groups like Neanderthals along the way.

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The DNA Revolution: Decoding Our Ancestry Ancient and Modern

Before we dive into what genetics has revealed, let’s step back and think about why DNA is such a game-changer for the study of evolution.

We all inherit DNA from mom (half from her) and dad (the other half). But DNA doesn’t just inform you about your parents. It bears information from all of your ancestors going back thousands, even millions, of years. Little differences between people in our DNA accrued slowly over time, and by comparing these differences among different folks or species, scientists have been able to figure out who’s related to whom — and when they split off from one another.

The real turning point arrived after scientists learned how to remove DNA from ancient bones. Scientists even obtained DNA from an extinct, zebra-like creature in 1984. But extracting DNA from ancient human bones was far more challenging. Human DNA degrades with time, especially in warmer climates. Years passed while technical advances accumulated before scientists could consistently read ancient human DNA.

And then, in 2010, a miracle occurred. A group led by scientist Svante Pääbo declared they had decoded the full genome of a Neanderthal, which is an extinct human species that disappeared approximately 40,000 years ago. This wasn’t just a tiny scrap of DNA; it was the entire instruction book. And what they discovered stunned the scientific community.

Technology Makes the Impossible Possible

Reading DNA has become dramatically better — and markedly cheaper. A full human genome cost about $100 million to sequence in 2003. Today, it’s less than $1,000. This means scientists now have the ability to analyze hundreds or even thousands of ancient genomes, not a few.

New methods also allow scientists to work with vanishingly small amounts of degraded DNA. Antique bones generally have little DNA remaining, and much of it is tainted by bacteria. Special techniques can then fish out the human DNA from this stew and reassemble it, like a jigsaw puzzle.

It’s a technological revolution, which means we are getting new discoveries about monthly. Ancient DNA labs dot the globe, and they are hurrying to sequence DNA from bones discovered in caves, burial sites or excavation pits on every continent.

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Neanderthals Live On Inside Us

Here’s a fun fact: If you’re of European, Asian or Native American descent, roughly 1-2% of your genome comes from Neanderthals. That may not seem like a lot, but it effectively means Neanderthals aren’t quite extinct; we all have a little bit of them inside us.

Early modern humans when they left Africa 60,000 to 70,000 years ago met Neanderthals who had inhabited Europe and Asia for hundreds of thousands of years. For years, scientists argued over whether members of these two groups ever had sex. Only a few said they didn’t have much in common. Still others identified what appeared to be hybrid bones.

DNA finally resolved the question for good. Absolutely we had children together, and they survived and passed on our genes. And this wasn’t something that happened once — it occurred many times over thousands of years.

What Neanderthals Gave Humanity

The Neanderthal DNA within living humans isn’t randomly distributed. Some Neanderthal genes became widespread because they helped people survive. Here’s what we got:

Genes Related to the Immune System: A lot of the Neanderthal genes hanging out in people today aid in defending against infection. As modern humans migrated into Europe and Asia, they found new diseases that other populations had evolved to deal with. Neanderthals had been suffering from these diseases for thousands of years, and they had developed resistance. By interbreeding, modern humans received a rapid immune system upgrade without having to wait thousands of years for evolution to build up these defenses on its own.

Skin And Hair: A few Neanderthal genes pertain to skin and hair color. These genes allowed Neanderthals to adapt to the dimmer levels of sunlight in Europe. Some of these same adaptations were inherited by modern Europeans.

Altitude Adaptation: It turns out some genes that have helped people live at high altitudes may have come from Neanderthals. This is evidence of how interbreeding endowed modern humans with useful weapons for survival.

Pain Tolerance: Some Neanderthal genes have been linked to how people feel pain, according to recent research. Both ancient and modern genes could be working together to help some people today feel more or less pain.

However, not all Neanderthal DNA was helpful. Neanderthal genes are rare in specific locations of the modern human genome, particularly those affecting fertility and brain function, scientists have found. This is a clue that some Neanderthal-human hybrids failed to reproduce or survive as well, and those genes faded away.

Neanderthal Gene Contributions

Gene	Type of Effect on Modern Humans	Population Most Affected
Immune system genes (TLR genes)	Enhanced resistance to infection	Europeans, Asians
Skin color genes (BNC2)	Less dark skin adaptation	Europeans
Blood clotting factors	Increased tendency to form clots	All non-Africans
Type 2 diabetes susceptibility	Higher risk for diabetes	Europeans, Asians
Depression susceptibility	Increased depression risk	Europeans

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The Denisovan Mystery

Neanderthals weren’t the only other human species our ancestors encountered. In 2010, researchers scrutinized a small finger bone from a cave in Siberia. The DNA revealed it belonged to a previously unknown human lineage, which scientists named Denisovans, after the cave.

The nuts thing about Denisovans is that we have almost no bones at all from them. What we know about anything comes mostly from DNA. But genetic evidence indicates that they were widespread in Asia and even had arrived on some islands in Southeast Asia.

Modern humans also interbred with the Denisovans. Those living in Papua New Guinea and Australia have about 5 percent Denisovan DNA — much more than the Neanderthal DNA found in Europeans. People in East Asia also possess modest levels of Denisovan ancestry.

The Superpower Gene from Denisovans

One of the coolest finds is a gene called EPAS1. This gene enables people to survive on the extremely high altitudes where there is hardly any oxygen. Tibetans have an unusual version of this gene that allows them to thrive on the Tibetan Plateau, more than 14,000 feet above sea level.

How did this gene arise? It turned out to be from the Denisovans, as DNA analysis confirmed. This gene is present only infrequently in other human populations, but it’s quite common among Tibetans. Scientists suspect that when modern humans migrated to the Tibetan Plateau, some of them interbred with Denisovans. So the offspring that had inherited the Denisovan altitude gene could fare much better — and thus, in time, this gene percolated throughout the population.

This is evolution playing out, and it happened quite recently, perhaps only 30,000 to 40,000 years ago. It demonstrates that interbreeding with other human species allowed our ancestors to survive in hostile environments.

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Africa’s Hidden Genetic Diversity

Most news about ancient DNA involves Neanderthals and Denisovans, but some of the most exciting findings are among African populations. Africa is the birthplace of humanity and the most genetically diverse continent on Earth.

Recent studies have turned up evidence that ancient Africans also interbred with other, long-gone human species. These are “ghost populations” of humans, because we don’t have bones or DNA samples from them — we’re looking at their genetic fingerprints only in the DNA of contemporary Africans.

Various African peoples bear evidence of interbreeding with various ghost species. And in West Africa, genetic analysis indicates mixing with an unidentified human species that branched off from modern humans more than 600,000 years ago. Other ghost populations have left their own marks in other parts of Africa.

This totally rewrites the picture of human evolution. It is not just a neat little story of modern humans in Africa and then outside. Instead, multiple human lineages occupied Africa for thousands of years at a time and sometimes mixed with one another leaving behind a genetic hodgepodge of relationships.

Why Africa Matters

Investigating African genetics is important, but also difficult. Ancient DNA does not preserve well in hot, humid climates, meaning that scientists have very few ancient African genomes to study. For the most part, what we do know is based on contemporary African DNA and trying to infer in reverse what must have happened.

But despite these difficulties, progress is being made. They are discovering that African populations were much more migratory than had been realized. These people settled rainforests, deserts, mountains and coasts, each population developing distinct genetic adaptations.

The relevance of African genetic diversity isn’t merely historical — it has immediate implications for medicine today. The vast majority of the genetic research has concentrated on people of European ancestry. But by studying African genetics, scientists can create treatments that are more effective and provide insights into diseases that affect Africans differently.

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Rapid Evolution Continues Today

The process didn’t end when modern humans swept out of Africa and spread across the world. Genetic studies have shown that humans are still evolving, only now the evolution can be recent and fast, with changes occurring over centuries or even decades, in really small isolated populations.

Milk Drinking

One well-known scenario is lactose tolerance. In most mammals, the ability to produce lactase — the enzyme needed to digest the sugar in milk — declines after infancy. Historically, most humans did too. But about 10,000 years ago, when people in Europe and some other regions began raising dairy animals as a result of an evolving culture that learned to herd animals for milk along with the development of animal husbandry that made livestock more docile, a genetic mutation developed that enabled the continued production of lactase into adulthood.

This mutation spread very quickly because it conferred upon people a tremendous advantage — the ability to obtain nutrition from food that others couldn’t digest. Today most people of Northern European heritage can drink milk without difficulty, while a majority of people of East Asian, African or Native American ancestry remain lactose intolerant. This is evolution occurring across a few hundred generations.

High Altitude Adaptations

In addition to the Tibetan EPAS1 from Denisovans, other populations evolved adaptations for high altitude independently. Another group of people in the Ethiopian highlands developed an entirely different genetic adaptation to low oxygen. And the Andeans of South America evolved a third suite of adaptations.

All three of these populations — Tibetans, Ethiopians and Andeans — face the same problem (low-oxygen conditions), but have developed different genetic solutions. This is known as convergent evolution, and it illustrates just how adaptable the human genome can be.

Malaria Resistance

In areas where malaria is endemic, the prevalence of several protective genetic factors has reached high frequency. The best known is the sickle cell trait. Having one copy of the sickle cell gene provides resistance to malaria, but two copies cause sickle cell disease.

This represents a genetic trade-off. The gene is bad in some ways, but good in others, so it survives where malaria remains a profound threat.

Examples of Recent Human Evolution

Gene	Population	Time Frame	Selective Pressure
Lactose tolerance (LCT gene)	Northern Europeans, East Africans	10,000 years	Dairy farming
High altitude adaptation (EPAS1)	Tibetans	30,000-40,000 years	Low oxygen
Sickle cell trait (HBB gene)	Sub-Saharan Africans	5,000-10,000 years	Malaria protection
Light skin pigmentation (SLC24A5)	Europeans	8,000-10,000 years	Low UV
Blue eyes (HERC2/OCA2)	Europeans	6,000-10,000 years	Sexual selection/UV

These and other genes are physical evidence that human beings have naturally evolved within relatively short periods of time.

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How the Farming Revolution Changed Our DNA

About 10,000 years ago we began the shift from hunting and gathering to farming. This was more than just a lifestyle change: It reshaped human genetics.

Once people settled down and began growing crops, their diets underwent a radical transformation. The researchers hypothesize that these people ate an increasing share of starchy foods, including wheat, rice and corn, but less meat and wild plants. This change in diet created new selective pressures.

Genes that made it easier to digest starches spread in farming populations. The gene AMY1, which is involved in starch digestion, appears to have been selected for lately. Individuals with added copies of this gene can process starches more efficiently — a clear benefit when consuming large amounts of grain.

Farming likewise meant that humans were in much closer contact with animals. Cattle, pigs and chickens and other forms of livestock shared or even lived inside human settlements. This made it easier for illnesses to jump from animals to human beings. Most of the infectious diseases that have killed citizens of historical civilizations such as smallpox, measles and tuberculosis were domesticated animal diseases.

The more people who lived in close quarters, with domestic animals crowding the space, the stronger the evolutionary need for good immune systems. Genes related to immune responses — in defending against infections, for example — have experienced recent natural selection in farming populations. Those whose ancestors farmed for many thousands of years have just slightly different immune systems than people whose own ancestors kept hunting and gathering for a bit longer.

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What Makes Humans Special?

By comparing human DNA with that of our nearest relatives — chimpanzees and bonobos — scientists can begin to work out which genetic changes were involved in making us uniquely human.

Chimpanzees are 98-99% identical in DNA to humans. 1-2% may not sound like a lot, but it contains many of the genes that influence brain size, brain development, language ability and other traits specific to our species.

The FOXP2 Gene

One of the most famous is FOXP2, known as the “language gene.” Humans possess a slightly different version of FOXP2 than other primates. Those with mutated forms of this gene typically face significant speech and language impairment. The version of FOXP2 that evolved in humans may have played a role by enabling the development of complex language.

Perhaps curiously, Neanderthals also possessed the same version of FOXP2 that we do. That indicates they may have been capable of some level of complex speech, though it’s unlikely we’ll ever be certain what their language sounded like.

Brain Development Genes

Numerous genes that participate in brain development exhibit signs of accelerated evolution in humans. The ASPM and microcephalin genes, for instance, influence brain size. The human versions of these genes may have helped to create our big, complex brains.

But it’s not just about size. The brains of human beings do not resemble those of other primates in how they are organized or develop. Human brains, of course, take much longer to mature — we have a long childhood compared with other animals and therefore more time to learn.

These days, researchers have pinpointed dozens of the genes that regulate when our brains begin to advance. Tiny alterations in these genes can have outsized effects on the development of brains. Knowing about these changes can allow us to understand how humans have propelled themselves to advanced thinking, planning, art and culture.

What We Still Don’t Know

Despite all that progress, science still can’t completely explain what makes us human. The genes we have found are only pieces of a much larger puzzle. Our uniqueness as a species probably arises from combinations of many genes acting together and cultural evolution superimposed on our genetic inheritance.

There are also the ways in which we differ from apes and all other animals — how much more we humans rely on culture, that is things we learn from others instead of inherit genetically. No other species has culture that’s as complex or changes as quickly as human culture. That interchange between genes and culture makes human evolution uniquely complex.

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Genetics and Human Migration

DNA is a bit like a set of breadcrumbs indicating where our forebears travelled. Scientists can track ancient migration routes with astonishing accuracy by comparing DNA from various populations.

All humans not only outside Africa but within it are descended from a relatively small group that left the continent between 60,000 to 70,000 years ago. From there, humans spread across the world with remarkable speed. Australia was reached by 50,000 years ago, Europe by about 45,000 years ago and the Americas at least 15-20,000 but possibly more than that (early dates for the Americas are elusive).

Genetic research has unveiled some of the secrets of these migrations. For instance, Native Americans are thought to be descended from a population of people who crossed over from Siberia into Alaska and then spread southward through the Americas. DNA reveals they arrived in multiple waves, not all at once.

Genetically, this expansion has also been described through the Pacific. Polynesians in outrigger canoes crisscrossed enormous swaths of distance, settling islands across millions of square miles of ocean. Their genetic material reveals where they came from and which islands they occupied first.

The Bottleneck Effect

Genetics does some interesting things when small groups leave and go somewhere else. These founding populations will contain only a subset of the genetic diversity present in the source population. This is what’s known as a “bottleneck effect.”

You can observe this in world genetic diversity. African populations have the greatest genetic diversity because they are where humans evolved and lived for a very long time. As populations spread further away from Africa, they passed through several bottlenecks which caused diversity to reduce. Genetic diversity is lower when humans finally walked into South America or far-off Pacific islands.

Such patterns help scientists in piecing together ancient migration routes and when those were established. DNA works like a clock — the more differences among populations, the longer they have been separated.

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The Future of Human Evolution: Where Are We Going?

Will humans continue evolving? Absolutely, but the forces that are driving evolution are different today from those of yesterday.

Modern medicine has upended the evolutionary game. Thanks to advances in medicine, even people with genetic conditions that would have been fatal a century ago can now survive and procreate, placing their genes into the world. Characteristics that could once have been “weeded out” by natural selection are now preserved in the gene pool.

So, are we “degrading” genetically? Not necessarily. Evolution doesn’t necessarily mean getting “better” — it’s about adapting to the environment. Presently our environment is one of modern medicine, and now we are evolving for that.

New Selective Pressures

Emerging life puts forward new evolutionary pressures, but they are also slow. For example:

Disease Resistance: We have selective pressure for new diseases, e.g. HIV. Some genetic variants naturally resist HIV. Over generations, these variants could be more prevalent.

Diet: Our diets are a lot more modern than those of our ancestors. That could exert pressure for genetic changes in metabolism, though we won’t see those develop for thousands of years.

Timing of Reproduction: People in rich countries are having children later. In theory, this might change which genes are passed down, but the effect would be subtle and slow.

Genetic Engineering

The biggest question about the future of human evolution has to do with genetic engineering. With technologies like CRISPR, scientists can now edit genes with precision. Might we be able to begin steering our own evolution?

This raises huge ethical questions. Should we edit human embryos to remove disease genes? What about enhancing traits such as intelligence or athleticism? Those questions will have different answers in different societies, and the stakes are high.

Some scientists are concerned that they will create genetic inequality — a world where rich people are able to afford genetic enhancements while the poor cannot. Others say we already “edit” ourselves through medicine and technology, and this is just more up close.

Whatever else happens, genetics is likely to increasingly influence human evolution in the future. We are no longer exclusively passive recipients of natural selection — we are increasingly active shapers of our genetic future.

For more information on the ethical implications of genetic engineering, visit the National Human Genome Research Institute.

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Frequently Asked Questions About Genetics and Human Evolution

What percent DNA do humans share with Neanderthals?

Non-African humans today have between 1 and 2 percent Neanderthal DNA. This DNA resulted from interbreeding that occurred when early modern humans left Africa and met Neanderthals in Europe and Asia.

Are humans still evolving today?

Yes, humans are still evolving. Recent evolution comprises lactose tolerance in dairy-farming populations, responses to high-altitude in Tibetans and Ethiopians, and disease resistance in various populations. Evolution is not as rapid as it was in our ancestral past because of modern medicine and technology, but it has not come to a standstill.

How come Africans don’t have any Neanderthal DNA?

Neanderthals inhabited Europe and Asia, not Africa. The interbreeding between modern humans and Neanderthals occurred after some humans had left Africa, but before they had dispersed throughout the continents. That means people whose ancestors never left Africa lack any trace of Neanderthal ancestry.

Can DNA tests pinpoint where your ancestors lived?

DNA testing can provide you general regions in which your ancestors probably lived, but it is not perfectly accurate. Those tests compare your DNA to reference populations, but people have been moving and mixing for thousands of years, so exact locations can be hard to pin down.

How do scientists extract DNA from fossils?

Researchers recover DNA from ancient bones and teeth by grinding small samples and applying special chemicals to isolate the DNA. The DNA is often degraded and entangled with bacterial DNA, requiring sophisticated procedures to recognize and reconstruct the ancient human’s DNA sequences.

What’s the difference between Neanderthals and Denisovans?

Both were humans, as was the Neanderthal and the Denisovan species, but all had different configurations of that ancestry. Neanderthals inhabited Europe and western Asia, and the Denisovans occupied eastern and southeastern Asia. They had distinct physical characteristics and genetic makeup, but they both interbred with modern humans.

Will genetic engineering end the evolution of humanity?

Genetic engineering technologies, such as CRISPR, could potentially impact human evolution because they enable us to modify genes directly. But this raises enormous ethical questions and most countries either limit or prohibit genetic editing of human embryos. The long-term impact remains uncertain.

How long does DNA last in bones?

Temperature is the greatest influence on the rate of DNA degradation. DNA, in cold, dry climates can last hundreds of thousands of years. In warm, moist habitats it degrades much more quickly — in a few thousand years, typically. That’s why we have much more ancient DNA from Europe and Siberia, for example, than tropical regions.

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The Story Continues

The story of human evolution is a very different one than we thought, as genetics has expanded our picture of the past. Each passing year serves to complicate the human story with fresh evidence.

We now understand that human evolution wasn’t a linear progression from ancient apes to ourselves. It was a disordered bush with many twiggy branches: different species of people that lived at the same time, sometimes met and had sex, sometimes went extinct.

The DNA within each of us is a mosaic. It carries fragments from ancient Africans, Neanderthals, Denisovans and perhaps other human species we don’t yet know about. Our ancestors persevered because they were a mutable and imaginative lot, always learning from whoever was nearby — even other kinds of humans.

Now, modern genetics is providing us the means to read this history in our very own cells. And as technology continues to advance and we sequence more ancient DNA, we’ll learn even more about who we are and how we came to be.

So let’s face it: We’re the ones writing the next chapter in human evolution, and for the first time in history we’re actually able to be conscious about being part of that story. How we decide to use this knowledge will not only mold our understanding of the past, but determine humanity’s future.

The rewriting of human evolution in light of genetics is not over — in many respects it has only begun. Every ancient bone found, every genome sequenced and every genetic analysis conducted adds more information to the marvel of humanity’s origin story. And we might not yet have discovered the most exciting finds.

The story of how we have come to be who and what we are will become ever more fascinating. Every year, it seems, scientists find new snippets of DNA echoing in our genes and are interpreted as coming from archaic or otherwise unknown relatives. From ancient DNA in caves to surprising discoveries about our extinct cousins, modern technology is helping us answer questions that once seemed impossible even a decade ago.

Here is a look at ten of the most significant and recent findings that are helping to redefine what we know about the origins of our species. These findings batter down old theories, connect us to ancestors we didn’t even know we had, and show just how related all humans are to people who lived many hundreds of thousands of years ago. Whether you are a science buff or just interested in figuring out where the heck we humans come from, these revelations are sure to have you seeing our shared history in a whole new light.

1. Modern Humans Carry Denisovan DNA

by Gregory Cooper

Researchers in other words are not strangers to foreigners, but many years back in 2008 they found a small finger bone and a tooth from an unknown species in a cave located in Siberia. That tiny bone turned out to be part of an entirely new kind of archaic human we hadn’t known existed: the Denisovans. What’s extraordinary about this discovery is that we’ve found only a few Denisovan bones, and yet they lived across Asia and even slept with our ancestors.

Here’s why this finding is so significant: Many people alive today have Denisovan DNA in their genomes. If any of your ancestors lived in Southeast Asia, Papua New Guinea or Australia anyone with this heritage slightly more than three percent but less than five percent of the DNA transferred from that wandering human to you. This genetic material isn’t just sitting there idle — it actually helps some people survive better at high altitudes, by regulating their ability to process oxygen.

The Denisovan find proved to scientists that humans didn’t evolve in a straight line from apes. Instead, various types of humans overlapped in time and space, encountered one another and interbred. This mingling of genes made us more resistant to diseases and allowed us to better adapt to different environments we encountered across the world.

How Scientists Study Denisovan DNA

Researchers are able to extract ancient DNA from bones and teeth, and then compare it to the DNA of living humans. They can tell:

• Where Denisovans lived
• Who they interbred with
• And whatever traits they bequeathed us
• Their strategies for adapting to their environment

2. Homo Naledi: The Cave Discovery That Changed Everything

Back in 2013, a pair of cavers were digging around deep underground somewhere in South Africa when they made an incredible discovery — a chamber filled with more than 1,500 ancient human bones. The bones come from Homo naledi — a species that has scientists scratching their heads because it is so different-looking from us, modern humans.

Homo naledi had a peculiar combination of traits. Their brains were puny — about the size of an orange — just like some very old human ancestors. But their hands and feet were remarkably modern-looking. The biggest surprise came when scientists dated the bones and discovered that they were but 236,000 to 335,000 years old. That means Homo naledi coexisted with early modern humans, who had much larger brains.

The find raises fascinating questions: Could a creature with such a small brain make tools, use fire or even bury their dead? The location of the cave in which they were discovered is also evidence of intentional burial, and therefore that Homo naledi had to have complex thoughts even though it only had a little, child-sized brain. That flies in the face of our belief that only big-brained humans were capable of symbolic thought or had culture.

3. Ancient DNA from Dirt Tells Stories of Lost Populations

One of the coolest advances in recent years is that scientists can now pull human DNA from soil and sediment — no bones required. This process, known as sediment DNA analysis, is akin to finding the genetic fingerprints of people who lived thousands of years ago.

In caves once inhabited by ancient humans, they left behind DNA in skin cells, hair and more. That DNA falls into the soil and can persist for hundreds of thousands of years. Using this technique, scientists have identified different species of human that lived at separate times in the same caves — even when they haven’t found any bones.

This discovery is revolutionizing archeology, because bones are scarce — but dirt is everywhere. Researchers can now study ancient populations even in regions where no skeletons exist. From DNA in ancient trash piles, they can tell who lived where, when and even what animals they hunted.

Source of DNA	Information It Provides	Oldest Age Limit
Bones and teeth	Direct genetic data, physical traits	Up to 400,000 years
Sediment/soil	Population presence, species identification	Up to 240,000 years
Cave deposits	Diet, animals present, climate data	Varies widely

4. Real Hobbit People in Indonesia

In 2003, researchers discovered bones from tiny prehistoric humans that were about the size of hobbits on the Indonesian island of Flores. At 3.5 feet tall, they were known as “hobbits,” after the race of people in J.R.R. Tolkien’s books. Initially, many scientists assumed they were just modern humans with a disease that kept them small. But further investigation revealed that they were in fact a distinct species, dubbed Homo floresiensis.

The hobbits were walking Earth just 50,000 years ago, and may have overlapped with our own species. Even with their tiny bodies and little brains (their brains are one-third the size of ours), they fashioned stone tools, hunted pygmy elephants and managed to last hundreds of thousands of years on their island home.

This discovery demonstrated that human evolution was more varied than we thought. It also showed that smallness could be an asset on resource-limited islands — a phenomenon known as island dwarfism. The hobbits show you don’t need a bulging brain to succeed: all you need to do is thrive in your environment.

Why Size Doesn’t Determine Intelligence

The hobbits of Flores have valuable lessons for us:

• Brain size isn’t the only measure of what your brain can do
• Different environments favor different traits
• Human evolution generated more diversity than we thought
• Small brained species did use tools and had culture

5. Interbreeding Was Common, Not Rare

For many years, scientists thought that when modern humans moved out of Africa about 70,000 years ago, they completely replaced other hominins without mixing with them. This theory has been totally debunked by new genetic evidence. Our ancestors, it seems, were a lot more social with other human species than we had realized.

Our modern human DNA is a mash-up of at least three other distant ancestors: the Neanderthal, Denisovan and possibly other hominin species which are yet to be discovered. If you are of European or Asian descent, about 1-2% of your DNA comes from Neanderthals. People from Oceania have as much as 5 percent Denisovan DNA. Some groups even carry DNA from now-extinct “ghost” species that we’ve encountered so far only through their genes, not fossils.

And it wasn’t a freak one-off — it happened multiple times at different places. What’s more, the genes we received weren’t simply random. And many of them helped our ancestors survive. Some of those Neanderthal genes helped to improve our immune system, adapted us to cold environments, and even impacted the characteristics of our skin and hair. In other words, the handshake and hanky-panky with our fellow human species was a case of survival making us stronger.

6. Humans Departed Africa Far Earlier Than We Thought

Every few years, scientists push back their estimate of when humans first left Africa. Recent finds in China, the Middle East and Southeast Asia proved that humans had ventured far earlier into the world than a traditional theory could account for.

A human jawbone dating to 177,000-194,000 years old has recently been found in Israel in an astonishing discovery that will overturn ideas of the origin of our species. Stone tools and what may have been evidence of human remains from 100,000 to 120,000 years ago are among other sites in China. These finds indicate that there were several waves of migration, not just a single great exodus.

Some of these early migrants left no descendants in modern populations — they died out, or were absorbed by later waves. But their existence outside of Africa at such dates push back our migration timeline entirely. It implies that our ancestors were much more adventurous and mobile than we’d credited them. We didn’t suddenly wake up 70,000 years ago and decide to leave Africa — we had been exploring and attempting to settle new lands for tens of thousands of years prior to that.

7. Ancient Art and Symbolism Came Well Before Previously Thought

For decades, scientists thought complex thought and art didn’t spark until humans matured in Europe around 40,000 years ago. This Eurocentric understanding was broken down by recent findings in Africa, Asia and elsewhere.

In South Africa, researchers found a trove of symbolic behavior dating back 100,000 years that included shell beads and engraved ochre along with sophisticated tools. Researchers in Indonesia found cave art they determined to be at least 44,000 years old — just as old as any of the famous cave paintings in Europe. Even more astonishing, there is some evidence that Neanderthals made art, and used pigment for decoration.

The results show that the ability of symbolic thinking, creativity and culture is not the preserve of a particular population or time period. People all around the world were making art, producing jewelry and symbolically representing themselves long before we’d previously thought. This would move back the roots of human culture and imply that the cognitive capacities that make them “modern” developed early in humans, not suddenly, in one place.

Timeline of Symbolic Behavior

Time Period	Location	Evidence
100,000+ years ago	South Africa	Shell beads, engraved ochre
75,000 years ago	Kenya	Ostrich shell beads
65,000 years ago	Spain	Neanderthal cave paintings
44,000 years ago	Indonesia	Hand stencils, animal art
40,000 years ago	Europe	Cave paintings and sculptures

8. Climate Change Influenced Human Evolution More Than We Thought

In decades past, scientists paid far more attention to physical evolution — how we and our bodies had evolved. But now research is revealing that climate change also played a major role in human evolution. When the climate shifted, humans either adapted or went extinct.

Climate models and findings from archaeology show that big shifts in human evolution keep happening during episodes of incredibly rapid change. For example, the evolution of larger brains in our ancestors coincides with times when Africa grew drier and food supplies shifted. Man had to grow smarter to discover food in more difficult terrains.

The most intriguing is on variation. It was not just cold periods or warm periods that were important — it was fast climate movements. In a fast- and unpredictable-changing environment, it was exactly those humans who could adapt, innovate and problem-solve that survived. Those who couldn’t adapt disappeared. This climate instability, in fact, may have selected for the adaptability and creativity that defines humans today.

Learn more about human evolution and climate change at the Smithsonian’s National Museum of Natural History.

9. Fire’s Role Changed Everything

The discovery of fire isn’t new, in other words, but what we’ve learned recently about when people began to control fire has profound implications. New evidence from sites in South Africa indicates that humans were using fire some 170,000 years ago — which is a hundred thousand years earlier than archaeologists previously estimated.

Controlled fires were transformative to human evolution in many ways. By cooking food, more nutrients were released and less energy was needed for digestion, and that in turn gave our brains the opportunity to grow larger. The discovery of fire and, as a consequence the warmth it brings, allowed humans to move into colder climates. It kept away predators and expanded the day with light after dark. Fire even served as a social center where families gathered, told stories and transmitted knowledge.

Our timeline has been pushed back significantly with the revelation in recent years of ancient hearths, burned bones and heated stones at archaeological sites throughout Africa and Asia. Some researchers now believe that it was mastering fire that was the key invention to separate us from other primates and perhaps led us down a path toward modern humans. Without fire, we might never have thought our way into big brains and large vocabularies; to say nothing of the chance it gave us to spread like sparks light up a landscape.

10. Genetics Exposes The “Ghost” Populations We’ve Never Discovered

Maybe the most bizarre discovery of recent years is that scientists can now tell when and where extinct human populations lived based solely on their genes — people for whom we have never found a single bone. These “ghost” populations appear as odd patterns in the DNA of modern humans that can’t be explained by any formally recognized species.

With the help of elaborate computer models, researchers can attempt to trace the ancestry of modern populations and discern areas where unknown groups may have contributed DNA. For instance, a former archaic human group that broke off from our lineage more than 600,000 years ago left its genetic mark in the genomes of West African populations. We’ve found similar ghost populations in Asian/Pacific Islander genetics.

It’s like finding the footprints of someone who has walked by but is not around. We may never recover bones or artifacts from these populations, but we can tell they were there because they left their footprints in our genes. The finding shows that the human family tree is more complex than had been suspected, and likely carried more branches than we can probably still discover, but added to who we are today.

How Scientists Detect Ghost Populations

Researchers use these methods:

• Compare DNA from present day humans in various regions
• Search for genetic patterns that do not correspond to any known ancient humans
• Model mixing with computers to simulate mixing scenarios
• Determine when and where these ghosts lived
• Calculate how much they contributed to modern DNA

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Why It Matters: These Findings Have Broader Implications

These 10 discoveries are more than just fun facts for scientists — they alter our very collective self-image. They reveal human evolution to be messy, complicated and much more interesting than a straight line from ape to human. We weren’t the only humans on Earth for much of our history; we lived alongside cousins like the Neanderthals, Denisovans and hobbits.

The findings also suggest that all living humans today are related to one another, carrying bits and pieces of DNA from these various ancient populations. No human “pure” lineage—we are all mixed. This scientific reality undermines racist theories about superior or inferior race, because we’re all literally cousins who share the same complex ancestries.

Lastly, these results demonstrate just how malleable humans can be. Our ancestors made it through ice ages, periods of drought and radical climate shifts. They made things up, and they figured things out. That same flexibility and innovation lives on in us today, which is heartening as we confront our own crises, from climate change to environmental degradation. Knowing where we came from helps us decode what comes next.

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Frequently Asked Questions

Q: How do researchers get DNA from ancient bones?

Researchers drill into bones or teeth to get powder, and then employ chemicals to extract DNA. They must be done in sterile labs, as ancient DNA is fragile and readily polluted with modern DNA. The DNA is then sequenced with powerful computers that can read even flawed genetic material.

Q: Could Neanderthals and Homo sapiens speak with one another?

This is a matter of debate, but available evidence indicates that Neanderthals had the physical capability to speak. They possessed a hyoid bone (crucial for speech) and the FOXP2 gene, which is linked to language. It is unknown whether they had fully modern language, but they likely communicated in complex fashions.

Q: Why did Neanderthals die out if they were smart and strong?

A number of factors likely played a role: climate change, competition with modern humans for resources, smaller population sizes that left them vulnerable, and perhaps diseases carried by modern humans. It probably wasn’t a single cause but a medley of challenges.

Q: Are there any unknown species of human still to be found?

Possibly! New species of ancient human are discovered all the time, and mysterious populations like ghost types can be found in DNA. There are even a few remote caves or sections that remain partially unexplored. Perhaps fossil discoveries yet to be made on the island will more directly represent unknown human relatives.

Q: What is the oldest human ancestor ever found?

That depends on what you mean by “human”. If you’re referring to the genus Homo itself (which we belong to), that’s around 2.8 million years old. If you’re talking about the hominins (animals that are closer to us than to chimpanzees) that dates back to around 6-7 million years ago with fossils like Sahelanthropus.

Q: How much more Neanderthal DNA do some people have than others?

Most non-African populations carry 1-2% Neanderthal DNA, although some individuals have a little more or less. Percentages are slightly higher for East Asians than Europeans. African populations have little or no Neanderthal DNA because their ancestors did not interbreed with Neanderthals outside of Africa.

Q: Will we ever be able to clone a Neanderthal?

This raises enormous ethical issues and is infeasible with technology that exists today. Despite the fact that we have a Neanderthal genome, we don’t have intact cells or eggs required for cloning. Most scientists would say that this shouldn’t be done even if it’s technically possible for moral reasons; making a person without their consent who would be completely alone in the world is unethical.

Q: How do scientists determine the age of fossils?

Depending on the age of the fossil, they employ various dating methods. Carbon dating is good for objects up to 50,000 years old. In older fossils, they use techniques including uranium-series dating, argon-argon dating and luminescence dating of surrounding sediments. Ages are typically verified through a number of methods.

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The Future of Research in Human Evolution

Never has the field of human evolution research moved so quickly. New technologies, including the analysis of ancient DNA and high-resolution imaging of fossils, as well as computer modeling of climate at a hitherto unthinkable level of detail has made it possible for scientists to ask and answer questions that would have been unimaginable just 20 years ago.

We will undoubtedly find more extinct species of humans, older bones with evidence of art and culture, and other details about how these groups interacted. Each find contributes another piece to our puzzle of where we came from and what it means to be human.

What’s even more exciting, however, is that anybody can follow along. New discoveries are always being announced and presented in laymen’s terms. The story of human evolution is not over — it’s being written today, with new chapters added constantly.

The next time you gaze into a mirror, think of the person looking back at you as the cumulative consequence of millions of years of evolution, climate change, migration and breeding between different human populations. You harbor DNA from ancient populations who lived before the spread of cities and writing. You’re part of a really long story — one that scientists are still piecing together, but one that tethers all human beings in all times and places. And that’s something worth appreciating.