Geneticist Spencer Wells

Guest interviews are usually available online within 24 hours of broadcast.

Renowned geneticist and anthropologist describes his work as director of National Geographic‘s Genographic Project.

Anthropologist and population geneticist Spencer Wells is an Explorer-in-Residence at National Geographic, where he leads the Genographic Project, using DNA to map human migration form Africa. His research has traced all of humanity back to a single man. Wells holds a Ph.D. from Harvard and was a research fellow at Oxford. In his book The Journey of Man—which was made into a film that aired on PBS—he traced migration around the world over the past 50,000 years. He examines our cultural inheritance in his latest, Pandora's Seed.


Tavis: Spencer Wells is a noted geneticist whose book, “Journey of Man,” was made into a very popular PBS documentary back in 2003. His latest project is called “Pandora’s Seed: The Unforeseen Cost of Civilization.” Dr. Wells, good to have you on the program, sir.
Dr. Spencer Wells: Great to be here, Tavis.
Tavis: When we say “The Unforeseen Cost of Civilization,” we mean by that what?
Wells: Well, we developed farming, the dawn of agriculture, about 10,000 years ago. Several places around the world, in the Middle East, the Fertile Crescent we’ve all learned about in school and in southeast Asia and China rice agriculture, corn agriculture in Mojacar and southern Mexico, and the question is why did it happen then? It turns out that there were climactic reasons, climactic shifts that were going on, something called the Younger Dryas, that put a lot of pressure on the early populations and we needed to develop agriculture in order to survive.
It made sense at the time. It allowed people to increase, the population to increase in size, but as they increased in size it created complexities – social complexities, also food complexities. So we had a complete shift in the sort of diet that we were eating.
If you go back to the time when we were all living as hunter-gatherers, which we were for most of our history, millions of years as hominids, we were subsisting on hundreds of different plant species, lots of different animal species. When we settle down and become farmers we start to focus in on just a few grain species and relatively high glycemic index, as we say these days, and so a lot of carbohydrates.
That had a profound effect on our biology and we’re still adapting to those changes as a result.
Tavis: Are you suggesting, then, that the cost to civilization has been primarily physical?
Wells: It’s been physical. Certainly if you look at the rise in obesity, the rise in diabetes and so on that we’re talking about today, very much in the news. It’s also been mental. We were really adapted to live in relatively small hunter-gatherer bands, numbering no more than maybe 150. That seems to be the optimal number.
Suddenly we’re living in megacities with millions of people and we’re bombarded with stimuli all the time, and how do we make sense of it? I think our brains are still trying to figure that out.
Tavis: You are what’s known as a population geneticist.
Wells: That’s right; I have a Ph.D. in genetics.
Tavis: Exactly – which means what, population geneticist?
Wells: Well, we study human diversity, in effect. We try to make sense of it. We look around the world and see people who seem to be so different from each other and from ourselves. How did that diversity arise, how did those differences arise? So we use the tools of genetics to piece together how we’re all related to each other and how we produce those patterns.
Tavis: Why is it, and put another way, how is it that you all can learn so much from DNA?
Wells: Well, DNA is a tool to unlock details about your ancestry, so the idea is we approach the study of human diversity as a genealogical problem. If you’ve ever constructed a family tree, the way you do that is you start in the present and you work your way back into the past, adding ever-more-distant relationships.
At some point, everybody who’s doing that reaches what the genealogists call a brick wall, and that’s a point beyond which we can’t say anything about our history and we simply enter this dark and mysterious realm where we kind of guess that we might be related to people. It turns out we’re carrying a DNA thread that goes back through all the generations that preceded us that allows us to see back to the very earliest days of our species, and so that’s what DNA does.
We pass on information every generation; we have our DNA that we got from our parents, that got it from their parents, all the way back to the very first parents.
Tavis: You brought me one of these kits. Let me ask you to explain what this kit is first, and then I’ll follow with my question, if I can.
Wells: Okay. So as you said, I’m a population geneticist. I direct a project at “National Geographic,” which is a research partnership between “National Geographic” and IBM. It’s called the Genographic Project. We are sampling DNA from hundreds of thousands of people around the world to figure out how these patterns of diversity arose and how our species emerged from an African homeland in the last 50,000 to 60,000 years to populate the entire plant.
So we’re asking members of the general public – this is all nonprofit – to order one of these kits if they’re interested in becoming a part of the project. So far, about 350,000 people have done that. So you swab your cheek, send off your DNA sample to the lab and a few weeks later you get it back on a website, totally anonymously, and see how you fit into this emerging family tree.
Tavis: Tell me more about what you hope to glean, to learn, you and the team, from the project.
Wells: What we are hoping to figure out is again the answer to this question of how do we generate this diversity that we see around us, all the different skin colors and hair types and eye shapes and so on, and how did we migrate around the world over the last 50,000 to 60,000 years?
If you go back to 70,000 years ago, our species was on the brink of extinctions. There were as few as 2,000 people living only in Africa at that time. We came back from that near-extinction event to expand around the world – seven billion people, nearly, alive today. How did that happen?
Tavis: There are some who believe, for different reasons, as you know, that we’re on the verge of extinction again. You respond to that how? (Laughter) You know what I mean by this.
Wells: In what sense? In what sense? The whole 2012 thing, or?
Tavis: Just that the world is unsustainable.
Wells: Well, I certainly do think that it is unsustainable, and that’s certainly something I talk about in “Pandora’s Seed.” I think we’ve set in motion a lot of events when we developed agriculture where we suddenly have this amazing power, and I don’t think our brains have kind of gotten a handle on what that means yet and how we control it.
I don’t think we’re on the verge of extinction, but I think we’re at a crisis point and I think that we are living unsustainably. If you listen to the United Nations, which I think they’re probably the best source, the world population is going to approach nine billion or even 10 billion by the middle of this century.
Are we capable of supporting that many people on the planet? Yes, I think so, but not living in the way we in the United States and Western Europeans even do. Nine billion people driving SUVs is not a good idea. So I think there’s going to have to be a profound shift in the way we relate to nature and to each other over the next few generations.
Tavis: Now you’re on to something that I find fascinating. How is it, given that we have become accustomed to living in the way that we do, given beyond that that everybody wants stuff, and that the more stuff you have the greater status you have, and everybody wants to have status, we all want our 15 minutes of fame.
How is it that with all of that said, and I could obviously go on here, with all that said, how is it that we never get traction on recognizing that if we don’t fundamentally shift the way we do business, if we don’t fundamentally change the way we operate, then we are, to your point, ultimately going to extinct ourselves?
Wells: That’s a good question. I think the only way it’s going to happen is if we start to see the costs of living in this way. So that’s the reason for the cap and trade carbon tax and so on that people are trying to implement. When the cost of gas goes up to $5 a gallon, then people start to notice it and they want cars that get better gas mileage. I think until we see the costs we’re not going to react, and I think that’s something that has been seen time and time again in our history as a species.
We really are capable of doing almost anything, but we have to see the true cost before we can act on it.
Tavis: What do you make of what appears at least to be a dramatic increase in the interest of this kind of work, and the range is pretty significant. There’s you and the project you’re working on, there’s Lisa Kudrow, of all people, from “Friends.”
Wells: And Skip Gates.
Tavis: There’s Skip Gates at Harvard. A lot of people are getting in this business of swabbing your cheeks and learning something about your past, so a couple of questions here, starting with what do you make of, again, what appears to be an increase in people wanting to participate in these kinds of projects?
Wells: Well, I think that’s a positive thing. It’s great to see people showing interest in DNA. DNA’s a fascinating tool for discovering things about your past, things you may never have suspected, even discovering long-lost relatives. So I think that it’s a generally positive thing.
For me as a scientist more information is better, and so this is part of who you are. It doesn’t define you, your DNA alone is not going to tell you your identity, but it’s part of what goes into making up your identity so I think it’s a positive thing.
Tavis: It may have been “60 Minutes,” it may have been something else – I think it was “60 Minutes.” Some time ago I saw a good piece they did on whether or not all of this stuff is reliable, whether or not it’s all – not talking about you now, but just this whole burgeoning and growing field, whether or not it’s reliable, whether or not one can trust it.
As is the case with anything else in this society, eventually people figure out they can run a hoax by telling folk about their past. How do you know what the heck you’re getting is real?
Wells: Well, I think it runs the gamut. I think there are perhaps some organizations or companies out there that are not as reliable as others. We make every effort to limit ourselves to what the science tells us and what’s supportable scientifically.
When we launched the Genographic Project back in 2005 there were maybe 20 or 25,000 people who’d had their DNA tested. There were three, possibly four companies at that time that were offering the service. It was very much a cottage industry.
We sold 10,000 kits in the first day and 100,000 in the first eight months, and we’ve sold now about 350,000 of them, so suddenly there is an industry and it’s spawned I think at last count something like 60 different companies offering these testing services.
Again, they run the gamut from those that maybe are not so reliable to people like us and a few other companies who I think actually do say things that are scientifically supported.
The key is to have access to the database and to interpret the data in the right way, and not over-interpret it. It’s very difficult to say, if you’re carrying a particular genetic lineage, that it’s only found in one particular group, and I think this is true for a lot of African Americans who know very little about the African side of their ancestry. They want to connect back to a particular tribe, perhaps, in West Africa.
The problem is the database isn’t quite there yet. You can say that yes, your lineage is present in the Fulani or whatever it might be, but you don’t know that it’s not present in other groups because we don’t have all the samples yet. So the key is to have access to that large database, and that’s what we’re trying to create with the Genographic Project.
Tavis: One of the things that turns me on about this – I was never great in science – one of the things I always loved about science was the whole notion of discovery. That this is one of those fields that if you dedicate yourself to it you’re going to learn things, you’re going to discover things – I mean, that is essentially what the study of science is all about.
I raise that because I want to ask, in the writing of this book and in the work that you’re doing on this project, tell me some things you’ve discovered that have surprised you.
Wells: The biggest surprise to us as population geneticists is the recency with which we all emerged from Africa. So if you go back even a couple of decades and ask physical anthropologists how long have people been expanding around the world, how long have they been diverging from each other, most people probably would have guessed a million years or more.
At the time of homo erectus, you had this human ancestor that left Africa and then you had the “races,” in quotes, of all things separately around the world.
What the genetic data has shown resoundingly is that we all trace back to an African ancestry very, very recently – within the last 50,000 to 60,000 years. That’s only about 2,000 human generations, so within that very short span of time in a broad, evolutionary sense, we have expanded around the world and produced all the diversity we see today. So that’s really the thing that just I find most amazing. It blows me away.
Tavis: I suspect you figure that there are a lot more surprises that await you.
Wells: Oh, definitely. We’re just beginning to get our teeth into the data – very exciting.
Tavis: Good. The new book from Spencer Wells is called “Pandora’s Seed: The Unforeseen Cost of Civilization.” Spencer, good to have you on this program.
Wells: Thanks a lot, Tavis. Good being here.
Tavis: My pleasure.
[Walmart – Save money. Live better.]

Announcer: Nationwide Insurance proudly supports Tavis Smiley. Tavis and Nationwide Insurance – working to improve financial literacy and the economic empowerment that comes with it. Nationwide is on your side.
And by contributions to your PBS station from viewers like you. Thank you.

Last modified: April 26, 2011 at 12:28 pm