Journey of Man: A Genetic Odyssey

Photo Credit: Mark Read/National Geographic Channels International

By analyzing DNA from people in all regions of the world, geneticist Spencer Wells has concluded that all humans alive today are descended from a single man who lived in Africa around 60,000 years ago. Of course, not everyone agrees with him. Modern humans, he contends, didn't start their spread across the globe until after that time. Wells addresses these issues his book, The Journey of Man: A Genetic Odyssey, and a National Geographic documentary of the same title. In a straightforward story, he explains how he traced the exodus of modern humans from Africa by analyzing genetic changes in DNA from the y-chromosome. The Journey of Man: A Genetic Odyssey airs Monday, March 12 at 8 p.m. on WXXI-TV/HD (DT21.1/cable 1011 and 11).Viewers will learn more about Wells's presentation at Monroe Community College in Arpil 2012, and how to get tickets.

Wells's take on the origins of modern humans and how they came to populate the rest of the planet is bound to be controversial. His work adds to an already crowded field of opposing hypotheses proposed by those who seek answers in "stones and bones"—archaeologists and paleoanthropologists—and those who seek them in our blood—population geneticists and molecular biologists.

Over the last decade, major debate on whether early humans evolved in Africa or elsewhere, when they began outward migration, where they went, and whether they interbred with or replaced archaic species has moved out of scientific journals and into the public consciousness.

"As often happens in science," he said, "technology has opened up a field to new ways of answering old questions—often providing startling answers."