Tracing Human Migration Through DNA

Geneticists are tracing the movements of people in prehistoric Europe using our DNA as a time machine.

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Every inside cell of our body is a kind of history book. Our DNA contains the story of our lives as well as the lives of our parents' lives, their parents' lives and so on. Now, scientists have been using the DNA in our cells to try to learn more about how our ancient ancestors moved around the planet.

NPR and National Geographic are traveling the prime meridian this year, looking at how climate affects people's lives in history. This month, we're in Europe. And for our series Climate Connections, NPR science correspondent Joe Palca looks at how geneticists are tracing the movements of people in pre-historic Europe.

JOE PALCA: Around 10,000 years ago, not far from where I'm standing now, a migration was beginning. I'm on an Atlantic Ocean beach in Southwestern France. From here, people started trickling north, returning to lands they had fled when glaciers had spread over Northern Europe. It's a migration that scientists are learning more about by applying the tools of genetics.

To understand how geneticists are tracking the movements of ancient people, I'll use the magic of radio to transport us from this beach in France to a hilltop on the outskirts of London.

We're standing, actually, on Observatory Hill, and we're about, oh, I don't know, 75 yards from the prime meridian. And I'm standing here with Mr. Lawrence Jenkins(ph).

Mr. LAWRENCE JENKINS: Yes. And I live in this part of the world. And I feel very blessed that I do.

PALCA: Mr. Jenkins is a real British gentleman, with a ruddy complexion and a tweed cap.

Mr. JENKINS: Immediately, I'm in front of this (unintelligible) house, just down the hill, they've got the…

PALCA: Lawrence Jenkins certainly knows his architectural history. And like many of us, he's curious to know about his personal history. So Jenkins decided to use his own DNA to take an amazing journey back in time, but not just a couple of generations.

Mr. JENKINS: I was interested in actually trying to go one big leap much further back.

PALCA: Can thousand years back in time far enough that he ran smack into the last Ice Age, a time when the lovely, green British Isles and much of Northern Europe was covered with a sheet of ice?

It was a chilly reminder that climate decides where people can live on this planet. So how does the DNA in our cells act like a time machine? Well, you can think of the DNA in our bodies as an ancient text handed down from generation to generation.

Professor BRYAN SYKES (Human Genetics, University of Oxford): And you can follow it way, way back, thousands - tens of thousands of years, the DNA has not changed a great deal.

PALCA: Bryan Sykes is a geneticist at the University of Oxford. He is one of those scientists who is learning to read that ancient text. Most of the time, the DNA doesn't change as it passes from generation to generation, but occasionally it does. With three billion letters of DNA, it's not hard to imagine a typo every now and then. And those tiny changes give people their own je ne sais quoi, their own genetic fingerprints.

Prof. SYKES: And so by comparing the genetic fingerprints of people in different parts of the world, you can have a pretty good idea where they've come from and how they've moved about.

PALCA: Sykes has formed a company called Oxford Ancestors that will test people's DNA and tell them where they came from. That was just what Lawrence Jenkins was looking for.

Mr. JENKINS: I contacted them. They sent me…

PALCA: For a few hundred quid, all he had to was use a Q-tip to scrape a few cells from the inside of his mouth.

Mr. JENKINS: Pop it in to a plastic envelope and send it to Oxford.

PALCA: The results were surprising.

(Soundbite of music)

PALCA: According to Sykes' analysis, Lawrence Jenkins' maternal ancestors didn't come from Europe at all. They came from Syria.

Mr. JENKINS: I couldn't believe it.

PALCA: And on Jenkins' father side, Bryan Sykes believes they came from another place that was sunny and warm 10,000 years ago.

(Soundbite of ocean)

PALCA: That place is near this beach in Southwest France. Mr. Jenkins' ancestors were taking refuge from the glaciers up north here, as well as further down the Atlantic coast all the way to Portugal. But when the Ice Age ended about 10,000 years ago, people from this region packed up granny and the kids and headed north.

Geneticist Bryan Sykes says most of the people who came to what are now the British Isles started out from southern France in the Iberian peninsula, because when he compares the DNA from people in Britain today with the DNA from people living in northern Spain and southern France…

Prof. SYKES: People in England and in Scotland and Wales and in Ireland have the same underlying genetic structure, which is essentially Celtic.

PALCA: Yes, said Celtic. Turns out, much to the surprise of Lawrence Jenkins and many others, the genetic evidence shows that most people in Britain are not the descendant from the Anglo-Saxons, but the Celts who came up from the south and populated Britain and much of the rest of Europe.

Mr. JENKINS: And the suggestion is that my ancestors were amongst the first people to arrive in the British Isles after the end of the Ice Age.

PALCA: So by combining genetic data, archeological data and climate data, scientists are getting a better picture of how people and climate interacted in the past.

But for Lawrence Jenkins, just as important is finding out where you fit in the world in which you find yourself…

Mr. JENKINS: I suppose it gives you a sense for identity with something. You feel a sort of greater kinship with everybody.

(Soundbite of music)

PALCA: Perhaps that's a good reminder. That if climate change makes part of the earth uninhabitable, it will affect someone we're related too, if not closely then through the last 10,00 years of human evolution.

Joe Palca, NPR News.

(Soundbite of music)

SIMON: Well, thank you for joining us this morning.

(Soudbite of laughter)

SIMON: And hope you enjoyed the flute music. You're listening to WEEKEND EDITION from NPR News.

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