By collecting blood samples from thousands of men living in isolated tribes around the world and analyzing their DNA, 34-year-old geneticist Spencer Wells and his colleagues discovered that all humans alive today can be traced back to a small tribe of hunter-gatherers who lived in Africa 60,000 years ago.
Following this genetic trail, Wells has charted the ancient journey of our ancestors as they populated the planet, continent by continent. The story is told in the 2002 National Geographic documentary The Journey of Man: A Genetic Odyssey and the book of the same name.
In 2005, Wells was named a National Geographic Explorer-in-Residence and became project leader of the Genographic Project, a sweeping five-year endeavor conducted by National Geographic, IBM, the Waitt Family Foundation, and a worldwide team of scientists. The Genographic Project is by far the largest genetic study of human migration ever undertaken.