Spencer Wells
The National GeoDirector, The Genographic Project

Why did humans suddenly start to migrate?

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For three-quarters of our history, we lived in Africa. Why did we suddenly start to leave?

Spencer Wells

Spencer Wells is a leading population geneticist and director of the Genographic Project from National Geographic and IBM. His fascination with the past has led the scientist, author, and documentary filmmaker to the farthest reaches of the globe in search of human populations who hold the history of humankind in their DNA. By studying humankind's family tree he hopes to close the gaps in our knowledge of human migration.

Wells's own journey of discovery began as a child whose zeal for history and biology led him to the University of Texas, where he enrolled at age 16, majored in biology, and graduated Phi Beta Kappa three years later. He then pursued his Ph.D. at Harvard University under the tutelage of distinguished evolutionary geneticist Richard Lewontin.

His landmark research findings led to advances in the understanding of the male Y chromosome and its ability to trace ancestral human migration. Wells then returned to academia where, at Oxford University, he served as director of the Population Genetics Research Group of the Wellcome Trust Centre for Human Genetics at Oxford.

Following a stint as head of research for a Massachusetts-based biotechnology company, Wells made the decision in 2001 to focus on communicating scientific discovery through books and documentary films. From that was born The Journey of Man: A Genetic Odyssey, an award-winning book and documentary that aired on PBS in the U.S. and National Geographic Channel internationally. Written and presented by Wells, the film chronicled his globe-circling, DNA-gathering expeditions in 2001-02 and laid the groundwork for the Genographic Project.


Question: Why did humans suddenly start to migrate? 

Spencer Wells: I don’t know, I mean some people think that what lead to that explosion would have been the development of language; that probably was a precondition for it, i.e. it was necessary but not necessarily sufficient, you know, creative thought whatever that means, however you define creativity, abstract thought which is probably why we see art appearing around that time and not before. We’re thinking about the way the world is and creating depictions of it which means we’re fully taking on board what it is and trying to modify perhaps in some way we realize that we have some control over it. What happened around that time is that we probably became innovation machines in a sense and innovation to me has a couple of components, one is that crazy person who, you know, stays up late and has the off the wall idea that nobody’s ever had before and the other is figuring out a way with the rest of the group to actually make it work okay. So you have the idea, the initial seed of an idea that perhaps occurs to one person, perhaps it happens to a group, but oftenit's one person and then the group has to work out a way to make it something that’s applicable to create a technology from the idea and that’s what seems to have occurred around that time. We became much better at innovating to, you know, develop new tools or to hunt with more, you know, with better methods or whatever it might have been. So, you know, to me was it a genetic change, I don’t know, it could have been genetic, it could have been driven by the cultural shifts by, you know, the need to, you know, survive in these rough conditions. Will we ever figure it out, I hope so, we might not, you know, there’s a lot of speculation, this is one of the big debates in physical anthropology, what happened around that time but it would be great to know the answer.

Question: What gaps would you like to fill discoveries? 

Spencer Wells: Yeah I mean there are a lot of holes that I think we need to fill. The first one being what happened in Africa around 70,000 years ago that allowed us to survive the near extinction, so the genetic evidence is that we dropped down to 2000 people, perhaps even fewer, don’t know for sure but, you know, a relatively small number compared to the number of people who are alive today and that might have been driven in part due to extreme climatic shifts some ice age and mega volcano in Sumatra and we came back from that and we came back in spades, we succeeded far beyond our wildest dreams if you will, so we not only survived in Africa but we expanded and we started to populate the rest of the world and the correlates with a change in culture which is the dawn of the late stone age where tools become more finely crafted, art makes its appearance, some linguists think that fully modern language appeared around that time, hunting techniques become more sophisticated. Evidence for a change perhaps in the way our brains our wired, debate about this, what caused that change in culture that allowed us to start to expand, to not only survive that really tough period but to come back from it and start to expand and succeed, we don’t know. You know, to me that is one of the Nobel Prize winning questions in anthropology, you know, what set all of this in motion, you know, for so long, for ¾s of our history as a species, we’re limited to Africa largely and a little bit of the middle east but basically we’re limited to Africa, ¾s of our history was spent on one continent and then in the space of no time at all, 2000 generations we explode around the world and we’re everywhere. You know, you think back to the European age of exploration, 16th, 17th, 18th centuries, people going all over the world exploring, finding remote islands out in the middle of the pacific. Think of Captain Cook discovering the Sandwich Islands, now called Hawaii. In every place they went there are people living there and they don’t question why that is, you know, it’s just normal, humans live everywhere, they’re I don’t know, like air, you know, just humans are expected to be everywhere and, you know, the question is why are we everywhere, how did we get there, you know, why was it normal for humans to be everywhere and, you know, again that is the thing that really motivates us to do the Genographic Project.



Recorded on: Mar 22 2008