NOVA

[ice creaking and groaning] [] [Eske Willerslev] When I was in school, if, uh... if you had said to my teachers, "Someday Eske will be a scientist," they would've laughed.

I mean...

I would have laughed too.

I was a rebel, a troublemaker.

I wasn't good at the typical things that people connect to being a scientist.

I was a school failure.

That's the truth.

[] But I think I have one capability which has proven super valuable...

I have a very good imagination.

[] I used to think I was born too late... when I realized "There's no frontiers left.

Everything is mapped."

But there is a frontier.

Our frontier is the deep past.

That is where we can still be explorers.

[] Our world is nothing like it was millions of years ago... but how can we travel back in time?

Is there a time machine?

Yes.

It's DNA.

It's ancient DNA.

[] I believe...

I hope, that one day, I will recover DNA that is millions of years old, and if we did, it would give us the first detailed picture we've ever had of life on a hot planet.

[] [insects buzzing] [birds chirping] [cacophony of seabirds in distance] [wind whispering] [Eske] In a single lifetime, it looks like nature sits in place.

[ice chipping] But human life is very short.

It's when you dig down, you see the evidence.

You go down and back in time... ...and then you see... ...nothing stays the same.

[clanking] [whirring] [sawing] [] [Eske] DNA is a blueprint, right?

It's the code makes you who are.

[] Different individuals have different DNA codes.

Different species have different DNA codes, so it means if you can pull out a piece of the DNA code, you can actually map it to all known DNA codes, all known blueprints, and then you can identify, well, what organism are we talking about here?

Twenty years ago, I came up with an idea that we might be able to find DNA in sediment.

In dirt.

In other words, in the environment.

I was ridiculed.

When you look out on the landscape, right, it's almost looking like you're at the moon or something, but of course you can see, if you look closer, you can see, well, there's a lot of vegetation here.

Right?

And, uh, well, there's also animals here, and all of that are leaving DNA traces behind.

Right?

So they're leaving, uh, you know, cells behind... and, uh... some of that DNA will even enter the lakes we have here.

So the mud in the bottom of the lakes can tell us what Iceland looked like before the Vikings came.

I mean, now, when you look around, it's all tundra.

But when the Vikings came here, it's said in the sagas that Iceland was covered by forest.

Can this really be true?

[] It turns out that it is true.

Iceland was covered with forests before the Vikings came 1,200 years ago.

[bird chirping] We have this awesome power to dig down, recovering ancient DNA from the dirt, and reconstruct entire living worlds.

But it's not a magic trick.

20 years after they laughed at me, finding DNA of ancient plants and animals in the dirt... well?

It's no big deal.

But to get here, the path I took to figuring it out, it was not a straight line.

My twin brother, Rane, and I are sons of a university professor.

But none of us wanted that life.

Our dream was to enter the wilderness, far away from any civilization.

We wanted to be trappers in Siberia.

[loon calling] So we learned to canoe, shoot, fish, and when most of our friends were entering university, we were heading off to Siberia.

So, it's hard to explain what inspired us.

I think it was a kind of romance, right?

[loons calling] You have to remember that before the Iron Curtain disappeared, we knew almost nothing of what it was like in Siberia.

[paddles splashing] It was the ultimate adventure.

Rane and I, we were paddling for weeks across these Siberian rivers in order to find an indigenous people called the Yukaghirs, and finally, we found the remaining part of the Yukaghirs.

And then Rane left, went back to Denmark.

I stayed... to work as a trapper.

[loons calling] I mean, it was a childhood dream.

Maybe I was hopelessly romantic, but I wanted to become a Yukaghir, live close to nature, just like they do.

It was the toughest thing I ever tried.

I mean, uh, in this area, temperatures are falling below minus-50 degrees Celsius, right?

You're working yourself to death in this cold.

[cutlery clinking] I was together with two other peoples, one Yukaghir and one Russian, and I remember during Christmas, our hunting had gone very bad for weeks, so we were basically out of food, and we were sitting, each with a cup of boiled water, and saying, "Merry Christmas."

At that point, I cried.

And I remember I said, "I will walk back to civilization," and the Yukaghir said to me, "Just forget about it.

You'll freeze to death before you get there."

So, most of these trappers, uh, they didn't pass 50 years of age.

Either they were killed, they went through the ice, drowned, got lost... there's so much alcohol, so much destruction, so much... violence.

So this whole experience that I thought would be a romantic experience, rather than building me up as a man, it ripped me apart.

It was brutal.

So I came back from Siberia totally exhausted, and, um... while also mentally unstable.

While I was there, my sister had died from AIDS, and I hadn't had a chance to say goodbye.

My father, of course, was devastated by her death and started getting dementia, so he wasn't there for me, and at the same time, my long-term girlfriend had dumped me.

So my friends at university were way ahead of me.

I was behind, and I didn't have a way to support myself.

So... if I wasn't a trapper, what was I?

So I thought, "Okay, man... good try."

There's no romance after all, and I didn't find the frontier I was looking for.

So this is where it ends.

I mean... [voice cracks] um... your life has no meaning, right?

And you have...

I didn't have, I...

I felt that life had no meaning and that I had no goals.

No clear goals, right?

What... what-what is there to become of me?

[] So I-I took my shotgun, and I loaded it, and I was basically about to pull the trigger... ...and then I looked out the window.

I remember I saw a tree... there was this tree.

[] And I thought, "Well, you know, in many ways, life is remarkable."

[] We're all connected.

I'm connected to the tree, right?

We have a common ancestor.

Life has been struggling to survive through millions and billions of years, and after all that, here I am today.

So it would be kind of laughing my ancestors in the face if I took my own life.

Suddenly, I could see something bigger, and... this was evolution.

It's the force that separates us from all other living things, but also the force that connects us to all other living things on Earth.

[] Well...

I took the gun and... unloaded it.

[] I got back to university, and, uh, I was in love with science.

I was in love with biology and genetics.

It kind of, well... gave me a rush, a new life.

I can compare it to being born again... ...but being born again into science.

[] Ever since I put my shotgun down, I've been hunting.

It's my obsession... to find the oldest DNA.

[airplane engine humming] The oldest DNA is the coldest DNA.

DNA's fragile, so it falls apart over time, but cold slows that process down.

When I look at this place, I see one huge cold storage room for ancient DNA.

Greenland has been covered by ice for a very long time.

What we are trying to recover is DNA millions of years older than any DNA ever recovered.

So we are trying to reach back before the last Ice Age.

No one has ever succeeded in getting DNA older than one million years.

Jurassic Park was not a documentary.

We are never going to bring dinosaurs back to life.

I'm sorry, but Jurassic Park never happened.

[] The early days of ancient DNA were a bit of a disaster.

Unless you're in PR, in which case, it was fantastic.

There was "dinosaur DNA."

There was "Miocene-aged DNA" preserved in fossils.

There was a whole bunch of what we now know is complete nonsense that was published with just abandon, just excitement and enthusiasm rather than actual science.

So let's reconstruct Jurassic Park.

Scientists go somewhere hot, because amber forms in hot places, and they find a really beautiful piece of amber, inside of which they can see this fantastic insect that looks perfectly preserved.

They take a big needle, and they stick it into the insect and they draw out... blood, presumably from a dinosaur, and then they take that blood to the lab and they do some magic that, for some reason, involves frogs, even though we already knew at the time that birds were the closest living ancestor of dinosaurs, and then more magic happens, and, uh, dinosaurs are back to life!

But we now know a lot more about DNA than we used to, and everything we know tells us, no question about it, that this molecule just doesn't stick around for millions and millions of years.

Dinosaurs have been extinct for more than 65 million years.

We will never get dinosaur DNA.

Jurassic Park is not gonna happen.

I'm sorry.

[] So, early on, we didn't know how long ancient DNA could survive, but there was a second really big hole in our understanding... contamination... ...ancient DNA getting mixed up with modern DNA.

[] Well, the trouble is that DNA is everywhere.

My DNA is now on this chair and on my hands and on my shirt and DNA is coming out of my mouth as I talk, and there is microbial DNA absolutely everywhere.

So when people were sequencing these bones, they were getting DNA, and they were saying, "Wow!

There's DNA in these bones!

It must be dinosaur DNA!"

I think there was some dinosaur DNA that was published that they were really excited about because it closely matched a bird.

Well... turns out the field excavation team was havin' a chicken dinner one night.

[] My memory of this was Hendrik had been working with his father, George, and they had together been involved in one of these... mm, potentially dubious really old "ancient DNA" papers.

We were really convinced, I think all of us, independently, that we had DNA of these insects actually from 20- to actually 120-million-year-old amber-entombed insects.

There was a naivete there, for sure, and there was certainly, uh, excitement.

I recall that when Hendrik's team announced the discovery of DNA from a 30-million-year-old bee, they gave the data to another group in London, to see if that group could replicate the results, and they couldn't.

That was really when the shoes started dropping.

People tried to replicate it.

They showed they couldn't replicate it, uh, and those are such critical moments in the field.

Yeah, it was a tearful moment, uh, for sure, but it was an important moment, because if you don't have self-correction, then you lose faith, not only in your own capabilities, but scientists around you.

You know, the public starts losing faith in science, and that's a more dangerous thing.

And so I do remember being sort of heart... [sighs] ...heartbroken by that.

Hendrik wanted to do it right.

Hendrik did a lot in the early days to establish these rules, and then has been a big proponent of making sure that other people coming into the field are doing our best to make sure that our results are valid.

I mean, everybody wants there to be dinosaur DNA, and so somebody who says, "Hey, I got this really well-preserved dinosaur, and guess what... there's DNA in it!"

Of course the media are gonna be super excited about this.

This is a field that brings science-fiction into science focus, and that is super exciting!

[] In 1995, I was a biology student and I wanted to do my research on ancient DNA, but I had no fossils.

teeth... Back then, you got DNA from bone, fossils, in other words.

I wasn't famous, so nobody wanted to give me fossils.

That was a bit of a problem.

You want to do ancient DNA, but you have no fossils.

I remember...

I was in my flat.

It was an awful day.

The rain was just coming down and leaves were falling from the trees, and I saw this woman out walking her dog, and she stops... [dog whimpers] ...the dog squats, takes a poop.

It's funny... inspiration sometimes comes out of the strangest times.

[he chuckles] I'm looking at this miserable wet dog, thinking, "Well, there's DNA in the dog..." so there's DNA in the dog poop, right?

[rain pattering] But will it survive?

We know there's DNA in the leaves, but we also do know that these things will disappear.

After next rainfall, the dog poop will disappear.

After a few years, the leaves will be gone.

The question I asked myself was, "What will happen to the DNA?

Will that be gone too?

Or will that be preserved in the soil?"

Because if it's preserved in the soil... ...we don't need any fossils.

Problem solved.

So, I remember, I went into, uh... the coffee room in the Department of Zoology where all the professors were sitting, you know, having their lunch, and I came with this idea, saying, "Well, what about looking in the soil for DNA of animals and plants?"

And they were laughing.

And my supervisor turned around, he was head of the department, saying, "Eske..." [speaking Danish] [faculty laughing] [Eske] "I never heard anything as stupid in my life."

No one had ever thought to recover DNA from dirt.

Why would it be there?

The idea is that DNA is kind of known to be such an unstable molecule in general.

If you're working in a molecular biology lab and you don't look after your DNA, it's gone very fast.

So yeah, it was a completely crazy idea that it would even be found.

I mean, that DNA enters the environment is obvious, if an animal urinates or defecates, but that DNA stays in the environment?

Completely crazy.

I mean, all animals are , right?

Leaving DNA in the ground for us to someday go and discover it... dirt DNA.

Well, this is how my career began.

[] [keyboard clacking faintly] [] [Beth] An organism's DNA contains the entire history of its evolution, not just it, but its species, its population, the family of animals that it comes from.

My DNA contains my history all the way from the beginning of life.

All organisms contain DNA, and all their DNA is fundamentally the same, made up of the same four letters, As, Cs, Gs, and Ts, the chemical code of life.

Getting DNA out of things that are alive is easy.

This is because modern DNA, DNA from living organisms, is in fantastic condition.

Long strands of DNA, if you can think of it kind of as party streamers.

Ancient DNA, rather than being like this party streamer of modern DNA, is more like confetti.

The reason that modern DNA, party streamers, get chopped up into the confetti that is ancient DNA is because of random processes that happen outside the body... mostly things like UV radiation from the sun.

When we walk outside, UV hits our skin, and it gets into our cells, and it damages our DNA.

But when we're alive, we have proofreading enzymes that will come along and fix those damages.

Otherwise, we would get cancer every time we walked outside.

But proofreading and fixing DNA, this is an energy-requiring process, and after you're dead, there is no more energy.

With ancient DNA, we're trying to go back in time, but time is the enemy.

Of course, we are never gonna stop wondering "Exactly how far back can we go?

What is the limit of DNA preservation?"

[Eske] In those early days, when I was still a student, we were all struggling with the problem of contamination, which was the big downfall of the "dinosaur DNA" guys of the '90s.

And I decided, well, somehow, we are going to solve that problem.

I was working on this with another student, Anders Hansen.

So we had this room that was basically our clean laboratory, but we had a problem with a mold contamination.

[] And in the end, we became so desperate, we decided, okay, we will basically clean the entire room down with very strong bleach.

We knew, well, it wasn't really allowed, and we didn't have money for gas masks... ...so we went in there on the weekend, and basically cleaned the room.

Anders got... got dizzy and threw up.

[scrubbing] And the security guard would just come in and say, "What the is going on here?

It's smelling like a swimming pool in the entire building."

And Monday morning, we were... had to stand in front of the professor and the lab director, and they were furious, right?

I mean, "What are you guys doing?

I mean, "Do you know this is totally illegal?"

But the good news was, even though we got all this heat, the fungi contamination were gone.

Finally... we had a clean lab.

At first, we tried getting DNA out of ice.

We got ice cores from Greenland, and we showed we could recover ancient fungi DNA trapped in the ice without contamination, and that was big.

So then we knew we were ready to move to the next step... searching for DNA in the dirt.

But there were still so many things I didn't understand.

[jet engines whooshing] So I went to Oxford... to one of the most exciting ancient DNA labs on the planet.

Beth Shapiro was there too.

[Beth] When I walked into Oxford, I knew the field was an absolute hot mess, but I also understood the potential.

The ability to recover DNA from bones was so powerful.

Eventually, while I was still there, um, Eske Willerslev joined us.

Those very first couple of years where it was just a few of us, they were probably the most exciting.

We felt like everything was just at our fingertips.

If we could break though, if we could figure out how to really get DNA out of these things, that we could believe, that we could trust...

I recognized that it was gonna be difficult, but I also didn't think it was going to be impossible, and I felt that we were really at a turning point for the field.

[Eske] Beth and I worked on some important papers.

She was a powerhouse.

I mean, she was one of the few pioneers really pushing the limits of ancient DNA.

And apart from Beth, it was all men... so she was a pioneer in that way too.

If, today, I were looking back at myself as I walked into Oxford on that first day, I think I would say, "Watch out.

You know what?

There are gonna be some bumps along the way, but ancient DNA is it.

Go for it."

In fact, I felt so strongly that ancient DNA was gonna become really, really big, I devoted my life to it.

[Eske] So, I really believed in this idea of environmental DNA or dirt DNA, and more than that, that it could survive in the environment as ancient DNA.

But I had to prove it.

So I set out to retrieve ancient DNA from the dirt, and at that point, no one had done that.

[drill buzzing] I don't really know why no one had looked at that before...

I mean, it wasn't that complicated.

If I could find a place where DNA is preserved frozen in time, I could recover it.

And I placed my bet on the Siberian permafrost.

[] Go back 12,000 years, and the Ice Age was ending.

Earlier than that, Earth was way colder.

The Ice Age, it's an amazing period, right?

It's the time of the big mammals.

You have giant wolves, giant beavers, mammoth, mastodons, right?

So I thought, imagine how much and urine these big mammals have been producing over time.

Right?

That is in the soil, in the surroundings, frozen in time, in the Arctic.

So my idea was to bring back that Ice Age world by retrieving DNA directly from the permafrost, and that permafrost I got from Siberia.

[buzzing and whirring] So while everyone else was looking for DNA in fossil, bone, and teeth, and discovering one species at a time, I was looking in the dirt for everything.

So, it's Christmas Eve, and I'm sitting alone in the lab.

Everybody has already gone home, right, for Christmas, and I'm basically checking the DNA sequences that we got out of the dirt.

I'm comparing those to all known DNA sequences in the world, and when I see the results, the hairs on my back are just rising.

It was bang!

Woolly mammoth.

It was bang!

Bison.

It was bang!

Reindeer.

It was bang!

Hare.

It was bang, bang, bang, different types of plants.

It worked better than I could even have imagined.

We were the first to show that plant and animal DNA can survive in the dirt, and we set a new record for DNA survival... up to 400,000 years old.

[Beth] The reason the technique of environmental DNA works is that DNA is everywhere.

It is raining DNA.

The very problem we had with DNA contaminating samples, that DNA is falling off of me and coming out of my mouth and floating in the air around me, that is exactly the opportunity we have with environmental DNA.

So I realized, it's not the scarcity of DNA that is limiting us.

Environmental DNA is everywhere.

The limit is time.

And this is really when I started thinking, well, how far back in time can we really push this?

[birds singing] This DNA from Siberian permafrost was my first big breakthrough.

That's how I became the youngest professor in Denmark... a full professor at 33.

It was a huge deal.

And I was in the first big race of my career.

[] I finally had the status, and the resources, to join the mainstream.

Now I was chasing ancient human DNA, and that's where the action really was.

[] My competition was with the big man in ancient DNA... Svante P��bo.

Svante would go on to win the Nobel Prize, but already, at that time, he was running the most famous ancient DNA lab in the world.

He was running around telling everybody that he was going to sequence the Neanderthal genome.

There definitely was a sense of being in a race on that project.

This field, ancient DNA, has always been very much shaped by who has the sample.

The group that I was working with, led by Svante P��bo, um, had kind of decades head start on everyone else.

I was young and ambitious, and trying to make a name for myself, so I decided, "I want to beat Svante."

If you discover something, you're the first.

Right?

If you're the second scientist to come along, you're a footnote.

Who wants to be a footnote?

Svante was a competitive person.

He would often say, "How's this gonna win me the Nobel Prize?"

[Eske] I could see that Svante and his team in Germany were going to sequence the Neanderthal.

No one could overtake him.

But I thought, "Maybe someone can beat him by sequencing the first ancient human."

I wanted to be that scientist.

I knew that the best chance of finding human DNA was in the Arctic, where the cold slows down the degradation of the genome.

And there was this long-standing mystery... who were the first humans in the Arctic?

We knew they were there because they left the stone shelters.

But who were they?

And where did they come from?

So, I just happen to get this invitation from a group of geologists to go up to Northeastern Greenland, and, uh, this is a remarkable place.

I mean, there you have, uh, something called the "Cape Copenhagen Formation," and it's a super dry and a super cold place.

Naturally, I thought Northern Greenland would hold the answer.

If really old DNA is going to be preserved anywhere, it's here.

It's ironic... the trip to Greenland was actually a failure.

We travelled all the way to Greenland, at huge costs, and we didn't find any ancient human remains.

We came home empty-handed.

And then a friend of mine told me, "Hey... there's some ancient human hair from Greenland in the National Museum of Denmark."

I mean, ten minutes' walk from my office, seriously!

And it was that hair that we sequenced.

[] I have to say, it's been like that often in my career... bad luck, and then crazy good luck.

And we published the first ancient human genome in February 2010, three months before Svante published the Neanderthal genome.

So we beat him!

[laughing] [camera crew laughs] [] This became front-page news all over the world, and I was in my 30s, and suddenly, I was famous.

Yeah!

[laughs] It was so good!

-[crew chuckles] [] That trip to Greenland felt like a waste of time, right?

We came home without any human DNA.

But we discovered something else that was... well, very important.

[] Northeastern Greenland... it's a very special place.

It's one of the most hostile places on Earth, extremely cold.

But even more important, this is an Arctic desert.

It was too dry for glaciers to form.

No glaciers to grind away the landscape.

The sediments up there are perfectly preserved.

In Kap Kobenhavn, you're literally walking on dirt from before the Ice Age.

[] It's incredible.

This place that is almost barren ground today, right... in the sediments, we discovered trunks of trees of wood that are three million years old, but is still preserved there.

So this told me two things... first, Cape Copenhagen must have looked very different in the past.

And secondly, this must be among the best places in the world for long-term preservation of DNA.

This gave me an idea... a naughty idea.

[he giggles] [] What if we could just dig in the dirt and recover DNA millions of years old?

It was a completely crazy idea, right?

Because at that time, no one, I mean no one, believed DNA could survive for millions of years.

If your goal is to get the oldest sample, then you go where that oldest sample is likely to be.

It reckons back to the age of exploration, right?

I mean, I-I think about... my kids are in 4th grade, so they're learning about the explorers that went around the world and this is kind of I think, how Eske sees himself a bit.

He's like, "Oh, you know what?

There's an Arctic desert.

I'm gonna go there, and I'm gonna get DNA from that."

And he will, because he's Eske, and that's how Eske works.

[laughing] In 2005, I published this review paper where we basically claimed, well, ancient DNA cannot survive for more than one million years.

That's the absolute limit.

But in the back of my head, I was still wondering, "is that really true?"

Right?

Could DNA survive longer than one million years in a place like the Cape Copenhagen Formation?

[] So, on that same expedition, I thought, "Hey, I mean, we're here.

Why not sample the sediments?

You never know.

We just might be able to find DNA."

I remember it was pretty miserable up there.

It was bleak.

It was cold.

We were working in a freezing Arctic desert.

Well, it rained, anyway.

Still, we cored into the frozen ground, and I got my crazy samples.

[helicopter rotors beating] So I took the sediment samples back to my lab in Copenhagen, and uh, to be honest, this was the beginning of a very frustrating project.

[] [Dr. Astrid Schmidt] Back then, I was a PhD student in Eske's lab, and when he offered me those samples from Greenland, of course I jumped on them.

I understood that I was taking on a high-risk project, and looking for DNA far older than any ever recovered.

At that time, Eske was a star in the scientific community, and I was inspired by Eske's enthusiasm.

We had a hypothesis that if the environment had been kept cold and the temperatures had not been moving up and down and fluctuated, then we would have had at least a possibility of finding endogenous ancient DNA.

So we're being, uh, optimistic, knowing it was a long shot, but also knowing that we could get groundbreaking results from this.

And there was DNA in the samples, we could see it, but it was super degraded.

A genome is like a twisted ladder.

If you think of a ladder, every rung is a base pair of nucleic acid, and each rung, each pair of bases, is made of two molecules.

Those are either "A" and "T" or "G" and "C." A human genome is incredibly long.

It has three billion base pairs.

That's three billion rungs on the ladder.

That's a big number.

[Astrid] When I started, the smallest fragment of DNA we could work with was about a hundred base pairs long.

That was simply the limit.

We did everything we could with the technology that existed, but we just couldn't overcome the central problem.

The Greenland DNA was just too old, the fragments were too short.

Yes, indeed, it was very frustrating.

The DNA, after one million years, was just total garbage.

Well, Astrid, uh... was one of many people in my lab that tried the Cape Copenhagen samples and basically failed.

In retrospect...

I was probably not a very good supervisor, right?

Because I-I kind of pushed for people to do these samples every time we had improvements of our methodology, in a hope, "Well, this time, they will work."

If that happened, it would be a career-booster.

But, uh... the risk associated with this project was huge, right?

So it was failure after failure.

Cape Copenhagen Project was, um... yeah, a bit sensitive.

As a postdoc, if you decided to invest your time in this, it was the case of having only so many years to be able to produce excellent research.

If you're not able to produce research because the technology doesn't allow it, not because you're a bad researcher, you still end up with nothing to show for it.

[Astrid] In 2013, I left research science, and I didn't pursue science, um, since then.

I took a big risk, and I paid a price.

So, Astrid, uh, she suffered the curse of the Greenland samples, and she was not the last one.

[] You have to understand that this is how scientific careers are made.

This is how I made my own career.

People said, "Well, there's no way you can do this.

It's impossible."

[] You have to take a risk to make a scientific career, and you also have to take a risk if you want to make groundbreaking science.

[] If you had asked one of my teachers, "Well, what will... what do you think will become of Eske?"

I'm pretty sure they would've said, "Well, worst-case scenario, he will be a criminal.

Best-case scenario, he will be a societal burden, a loser."

I mean, I remember in school, we were all asked to go up to the board and write a word, right, spell a word, and there was one of the students who said, "Well, has Eske been up to the board yet?"

And then the teacher looked at the board, "No, because there's no mistakes."

So...

I always was told, uh, as a kid, both by my family, by my parents, basically, my father, but also my teachers, "Well, you're not too smart, right, so you have to somehow compensate."

And, well, how can you compensate?

Well, you can compensate by hard work.

[] To be a successful scientist... it's not a job, it's a lifestyle.

There'll always be somebody who's willing to sacrifice more.

[] I mean, I'm sure my kids have suffered because of my work ethics.

My dad was like that.

I mean, my dad was exactly like that.

When I look back, he was always working.

It's hard to change yourself.

Sometimes I'll try to kind of say, you know, "Well, it's a holiday... you can't work," you know?

And I feel miserable.

I just can't really turn off, yeah?

That's the thing, right?

[indistinct chatter] [Beth] He is not afraid to call you in the middle of the night and remind you that you told him a few hours ago you were gonna do something for him.

He is that personality.

[laughs] I like working with Eske, but I also hate working with Eske.

It's, um... it's exciting to work with Eske, because he's so driven.

It's just drive, drive, drive, all the time, but it's also exhausting and kind of scary and infuriating at times, because you're like, "Yeah, this is cool stuff, but, Eske, I also have to sleep!"

[laughter] I think you often hear from, uh, scientists in interviews and stuff, "Oh, it's about the curiosity, and this is what is driving me," and all that, and that's true.

It's true, but it's not the whole truth, in my view.

You also have to have that drive of winning.

I have a demon on my shoulder.

I mean, it's, uh... [deep breath] Sometimes this approach can really piss people off, but I always have had this need for winning.

By winning...

I'm keeping away my demons.

[] It's been two decades of digging dirt up here.

When I look at the people who started this project, I'm almost the only one left.

Those early researchers on my team, they all left.

They basically quit science.

But new ones joined me.

I guess the prize was just too tempting.

[] I think this project's been going on for about 15 years.

I think I have had five colleagues who've been working on this as a PhD or as a postdoc, and actually haven't had success with these samples.

They not only stopped working on the project, but they left academia.

So, I was a PhD student in Eske Willerslev's lab, so you can imagine what I felt when this... these samples landed on my table.

Back in the day, we needed almost a hundred base pair fragments to survive in a sample in order to retrieve any DNA whatsoever.

[indistinct exchange] But the technology was changing and I had a student, Mikkel, who came to me with an idea.

I was immediately excited.

I thought, "Yes!

This could work."

Mikkel suggested we use a powerful new technique called shotgun sequencing.

Shotgun sequencing itself wasn't new, but no one had ever used it on dirt DNA.

I don't know why.

In retrospect, it seemed kind of obvious.

It really showed us that we could actually get ancient environmental DNA even from the very shortest threads that were preserving in the samples, And the obvious next step would actually be to take on the most challenging project of them all, what we refer to as "the curse"... the Cape Copenhagen Formation.

[] So in the early years of ancient DNA, we had to decide which part of the genome to look at.

Before, we had to target certain regions of a genome for sequencing.

Those are the giveaway parts of a genome that we call "barcodes."

They reveal the identity of an organism.

We matched those barcodes to our reference catalog, but those barcode fragments had to be long enough... over 100 base pairs.

Smaller than that, no results, nothing.

And we know that DNA fragments of that length just doesn't survive millions of years, even frozen high up in the Arctic.

Shotgun sequencing was a revolution.

Now, instead of targeting a specific part of the genome with precision, like with a rifle, we're using shotgun.

A shotgun hits everything, right?

With the shotgun method, we just sequenced all the DNA we can find.

Then we looked for matches with every genome sequence for every organism that we know of.

It takes immense computing power, billions of operations, and only now are computers powerful enough to work with fragments down to 30 base pairs.

Imagine shredding War and Peace.

All you have are short phrases, not even sentences, and you walk into the Library of Congress, and you start looking for a match for each one of those phrases, book by book by book.

There's another War and Peace in there somewhere, but you need to work through millions of other books before you find a match.

And once you do, your job is to reconstruct as many pages of that novel as you can.

So we were the first to use shotgun sequencing on dirt, and when we did... [deep breath] ...man.

It was powerful!

So, the methods that we used before, you can picture it as we were looking at the world through a keyhole.

But after shotgun sequencing, we were suddenly seeing, you know, through the whole door.

In science, moments like this actually feels like magic.

I have no other way of putting it.

It was just like that Christmas Eve 25 years ago.

As if by magic, we were seeing the genetic signatures of these plants and animals appear.

Bang!

Bang!

Bang!

But it's different this time.

Now... there's hundreds.

Shrews, lemmings, Arctic hare, geese, caribou... a whole forest ecosystem.

Larch, poplar, willow, spruce, fir, ash... cedar trees!

We're looking at a long list of organisms from a place that today is an Arctic desert.

Think about that.

That's what's so amazing.

Finally we are catching sight of the living world that existed in Greenland before the world grew cold... before the Ice Ages.

So I have to wonder, what weird world were these plants and animals actually from?

Because it's definitely nothing like today.

[] So today, we are in the Holocene.

That's about the last 12,000 years.

Before that, it was the Pleistocene, a period of lots of Ice Ages, more than 20, lasted about two and a half million years.

And before that was the Pliocene, when it was much warmer than the Pleistocene.

[animals growling] [Natalia Rybczynski] Yeah.

It was a really weird place, that world.

When you go back three million years, you're in a way warmer climate.

Earth was just hotter... ...and it had been that way for a very long time, since before the extinction of the dinosaurs, 65 million years ago.

[bird crying] I'm a vertebrate paleontologist.

I study the animals that lived in the Arctic before the Ice Age... mammals of the Pliocene Arctic.

The reality is, we don't know very much.

The time before the Ice Age began, the Pliocene, it's kind of a lost world.

We don't have full skeletons of any Pliocene mammals.

We just have fragments, shards of bone, evidence of maybe 13 species.

I still have so many questions.

For a paleontologist like me, it's really frustrating.

[hinges squeal] [Eske] So, after all those years, we broke the curse of the Greenland samples.

Suddenly, those samples were sexy.

[] But the DNA from Kap Kobenhavn, I guess you can say it was a breakthrough that immediately became a problem.

Was this a story that anyone would believe?

To be honest, we had to ask ourselves, can we really believe it?

[] We were able to retrieve DNA, small fragments, millions of years old, but the big question, of course, was how do such DNA survive beyond the one-million-year-old limit?

Before we told anyone about our results, that was the mystery we had to solve.

We created a new chemistry team, and what they discovered was fascinating.

It turns out DNA survived such an incredible long time because of minerals in the soil.

DNA is electrically charged, and many mineral particles that you find in the soil are also electrically charged.

So therefore, DNA fragments will basically bind itself around such sediment particles, and this will reduce the rate of degradation, of these spontaneous reactions that are attacking the DNA and breaking it up.

So yes, it will still be degraded, it will still be destroyed, but the rate by which this is happening is heavily reduced.

It turned out that particularly certain minerals of clay and quartz binds the DNA very strongly.

Bound to clay and quartz, DNA is basically frozen in time.

The magic... of minerals.

That was the moment.

That was when we knew we had something to tell the world.

We knew we were going to get hammered.

Extraordinary claims demand extraordinary evidence, right?

We had to be very sure about the dates from Cape Copenhagen.

That took two more years of hard work.

[] Finally, we were ready to submit the research to Nature Magazine, one of the most prestigious journals in the world.

We submitted.

And just like always with this project, that was the beginning of a difficult journey.

What is it that they are concerned about?

Whoever was reviewing, uh, our data, they were definitely skeptical.

We were reporting DNA over twice as old as the existing record, and not from a fossil, from dirt... ...but the DNA was there.

The dates was there.

We used five different dating methods, so we just kept providing more evidence, more data.

[] It went on for 15 bloody months.

I mean, have they contributed, uh, the papers part of their package?

It's a total catastrophe, right?

And then, as they say... [laughs] ... "Nature called."

[] Getting published in Nature , it's a big deal.

Getting on the cover, for scientists, it's like getting the cover of TIME.

And we got it.

We got the cover.

And then they said, "We want you to come to London for a live press conference to present our results to journalists all over the world."

[] And in all my years, that has never happened.

[] Today's briefing is for a paper entitled "A two-million-year-old Ecosystem in Greenland Uncovered by Environmental DNA."

We are joined today by six of the authors of that paper, so I'd now like to hand over to Professor Willerslev.

Thank you.

Yeah, okay.

Thank you so much for the introduction.

So, this is, uh, the longest study I ever been involved in, because we started already back in 2006, when we went to Northern Greenland to collect, uh, these samples, and every time we had improvements in terms of DNA extraction or sequencing technology, we tried... we revisited these samples, and we failed and we failed.

It kind of got, uh, the name in the lab, uh, "the Curse of the Cape Copenhagen Formation."

[] Well, it's two-million-year-old DNA from an ecosystem in Northern Greenland.

[] Until now, the record for DNA was one million years, of a single species... a mammoth that lived in the Ice Age.

Now... we have an entire living world at least twice as old as that mammoth.

[Beth] It feels almost magical to be able to infer such a complete picture of an ancient ecosystem, from tiny fragments of preserved DNA.

What is super cool about the Greenland breakthrough is the discovery that certain minerals can freeze DNA in time, because this means that everything we thought about the limits of DNA preservation are out the window.

When I first heard about the results from Kap Kobenhavn...

...I just said to myself...

"What?"

What we're talking about is pushing the record back to at least two million years, and I believe much longer than that.

It was a complete tour de force.

What are my feelings when I first saw this paper?

...is, uh, stunned.

I think we just never really thought it would be possible after years of trying to get DNA from these ancient ecosystems.

[] We never thought we'd see such a rich and diverse ecosystem in Greenland.

We're seeing the very last Arctic forests from a hotter world before the Ice Age... and these forests are unique.

We have nothing like them today.

[] It's a time machine, basically.

We built a time machine.

[loon calling out] [Eske] I always knew that there were forests in the high Arctic.

I touched the wood of ancient trees up there.

But when we looked at the sequences from Greenland, there was one that completely shocked me... it shocked everyone.

[roaring] For your average paleontologist, the idea of a mastodon in Greenland just doesn't sound plausible.

To hear that there was mastodon DNA from Kap Kobenhavn, this just struck me as, "Whoa!

How can that be?

That is so far north."

It comes completely out of the blue, and it was the first time that we found such a large animal in Greenland.

More surprisingly, that's never been found any fossil evidence of mastodons there.

[] [Eske] So these cores that no one believed in turned out to contain the most amazing treasure.

It just took us 15 years to find out how to get it out.

To be honest, I never really lost faith, because... every limit we have ever set, we broke.

An amazing journey, right?

It has taken us 16 years.

You have the paper came out, we published.

I feel, uh, relieved, and also exhausted.

[] It's kind of... "we're done," right?

[bird calling] [Beth] With environmental DNA, we're never getting the complete picture.

We can never know every form of life that lived in these lost worlds.

There must have been organisms that we miss.

We find the molecules that survive.

We find the DNA from the organisms that shed a lot of DNA.

Mastodons poop a lot, but maybe saber-tooth tigers don't.

Doesn't mean they weren't there.

[tigers roar] [Eske] No question.

We're not seeing everything that lived in the Pliocene.

So Natalia has this collection of bones from animals that lived before the last Ice Age.

She's got Pliocene fossils from Canada.

I've got Pliocene DNA from Greenland, so between fossils and DNA, we can now begin asking "how is that ancient world linked to ours?"

This was a really weird environment.

You had a forest where half the year, it was dark.

And the other half the year, it was sunshine all day around.

This means that all the organisms we are uncovering had to survive half the year in darkness.

[Natalia] So, one of the things I'm really interested in is how these northern forests, these Arctic forests, might have shaped the species we see today.

But what if hibernation in some mammals today actually came from when they were living at these high latitudes, in these dark winter forests, right?

Maybe this is where hibernation evolved for some lineages, such as bears.

We actually discovered a Pliocene bear fossil in Arctic Canada, but the fossil record doesn't give us evidence of hibernation.

In theory, we could find it, but we haven't.

That is where Eske and his DNA could really help us.

What if we could trace the evolution of hibernation using genetic evidence?

That would be very cool.

[water splashes] [bear grumbles] [] I think the thing that really blew our minds from the Pliocene... [low growling] ...is the camel.

When you think about camels today, it's really easy to imagine that they evolved to live in the desert, and this is where the finding of the high-Arctic camel is so mind-blowing, right?

Because... it's not in a desert.

It's living a complete opposite to a desert.

It's in a forest.

Ever notice how huge a camel's eye is?

Well, it turns out they have incredible vision, including night vision.

That's pretty useful when it's dark six months of the year.

One of the, uh, most dramatic features of the camel, it's the hump.

It's actually a specialized fat deposit, and when you think about the importance of fat, energy storage, this is something that's also very important for animals that survive through harsh winters.

The wide feet of camels, you know, it's listed as one of the traits that helps them walk over sand, also would function well in soft snow.

It's amazing, actually, when you think how life in the Arctic may have set camels up for life in the desert.

We haven't found bear or camel DNA from before the Ice Age... not yet.

But we have now recreated the forest world they were living in, and Natalia's fossils tell us they were there.

[wings beating] This is a forest that stretched from Greenland to Canada, on solid land without barriers.

[] We used to believe that ancient DNA could take you back a few thousand years.

Today, we know we can see millions of years back in time.

I guess the next question is, how far back are we really seeing?

So, we published the date of two million years, but it's important to understand that this is the minimum possible age.

Taking all the lines of the dating evidence as a whole, the most likely age of the Cape Copenhagen DNA is actually 2.5 million years.

This puts us into the late Pliocene, which is the period just before we start having glaciations.

If Eske's DNA is that old, if it is Pliocene, then that is huge, because, as it turns out, the time before the Ice Ages could tell us a lot about what is about to happen to us.

[] [Natalia] The epoch we're living in today is ending, so we need to look back to a hotter past, when life was very different.

We need to ask, "Is this a world where we could survive?"

[footsteps approaching] So, it's in cruise 28... and let's see... 179... -Wow!

-And you can just tell how much it's been sampled.

The Pliocene's a big, red flashing light, right?

The Pliocene seems very distant... filled with strange animals that are now extinct, but at the same time, it feels very close to me, as someone who studies climate.

The Pliocene was the last time atmospheric C02 levels were the same as today.

You have to go back three million years to find a climate equivalent to what we are doing right now... ...that is a C02 level of about 400 parts per million in the atmosphere.

Sometimes people say, "Well, we have the same amount of C02 in the atmosphere as the Pliocene, but we still have this giant Greenland Ice Cap, and we don't have forests around the Arctic.

What gives?"

And the reason for that is because the ice caps are really slow.

They have this really long response time, and you could think about it as, you know, you have a frozen lasagna, you put it in the oven, the oven's really hot, but it takes a long time for it to defrost, and that's what's going on right now.

We have the ice sheets, they're in this warm atmosphere, and they're rapidly losing mass.

They're melting, but it's gonna take them a long time.

One of the key questions of the Pliocene has always been how much of the polar ice sheets will melt, and by extension, how high will sea level rise?

And this has been a tricky question for a long time.

[gulls crying] Well, we finally found a site that tells us exactly how high Pliocene sea levels were.

It's in a cave in Spain.

[gulls crying] [] [Maureen] Sea levels were almost 50 feet higher... 16 meters.

Think about that.

It's a scary number.

It's a big number, and it's a scary number, 'cause you think about standing at the shore today, think about what 50 feet looks like.

Look up, and then imagine how far inland the ocean would be going with a 50-foot sea-level rise.

[water flooding] It's hard to imagine what our world looks like with even 20 feet of sea-level rise.

Even the coastlines around the world would look dramatically different.

Most of the major cities, Mumbai, Hamburg, London, New York, Los Angeles, everywhere you go... ...these cities are at risk.

But here's the thing... if we do nothing, and we just keep doing what we're doing, by the end of the 21st century, we will have a level of CO2 in the atmosphere, let's say around 800 parts per million, that now becomes equivalent to these time periods in the deep, deep past, like the Eocene, 50 million years ago.

[] The new Pliocene has begun.

It's called the Anthropocene.

We've already altered Earth's climate.

We're living in a climate that is about one degree C warmer globally than it should be.

This is not the first time we've had 400 parts per million of carbon dioxide in the atmosphere.

We've seen that deep in Earth's past.

However, it is the first time we've had eight billion people living on the planet.

[] The climate of the Pliocene is where we're going.

It's like our instruction manual for what's coming.

[bird calling] [Natalia] When the Pliocene ended and the Ice Age began, that was a big blow, but it didn't end life on Earth.

Every plant and animal you see today is a form of life that survived that change.

All life around us has its evolutionary roots in a hotter world, including us.

[] [Eske] So, what's next?

With these breakthroughs, a new era of ancient DNA is beginning.

Greenland proves we can go much deeper in time than what we thought we would.

We now have the technology to go even farther back in time, potentially many millions of years.

[] [Beth] We have access to the genetic codes of plants and animals that survived in different climates... hotter climates, drier climates.

If we can sequence the genomes of those ancient organisms, maybe they can help us... and I think we're gonna need help.

[] [Eske] We've already started.

This is the Carlsberg Lab in Copenhagen.

They create new food plants... like new variants of wheat, barley, rice.

We gave these scientists a piece of genetic code from the Cape Copenhagen.

It came from an ancient poplar tree.

These poplars grew in those weird Pliocene forests that could survive entire winters with no sun.

Yet, even in these extreme light conditions, the poplars could still photosynthesize.

So the folks at the Carlsberg lab copied those ancient poplar genes into this modern barley plant.

This is a food plant engineered for a hot future.

We are stealing genetic secrets of the past... ...so we can rescue the future.

I want to do my part to rescue the future.

[] We're going to sequence thousands, millions of ancient genomes from sediment samples all over the world.

[] Because we are now using robots across the entire pipeline, we can do 200 samples a week.

[] We are starting an Industrial Revolution in ancient DNA sequencing... [] ...with all that information about past life, going all the way back to the Pliocene.

Arctic barley is just the start.

[] Today we take for granted that all organisms are shedding DNA around in the environment, but once, this was a new idea, right?

And it all started with that dog in the rain.

And this is why we can do this... where a little bit of dirt contains an entire living world.

[]