Eight years ago, researchers “found” the mother of all humans, the proverbial Eve. By peeking into the cells of several ethnic groups, they traced the family tree of modern humans back 200,000 years to a single – albeit theoretical – woman. “Mitochondrial Eve,” named for the part of the cell passed from the mother and examined in the study, was hardly the only female human who was bearing children at the time, but scientists said her genes were the ones that endured.
Now, Eve has an Adam. In two reports in last week’s Nature, researchers suggest that virtually all modern men – 99.9 percent of them, says one scientist – are closely related genetically and share genes with one male ancestor, dubbed “Y chromosome Adam.” Unlike other chromosomes, Y’s are passed strictly from father to son, thus enabling scientists to follow the human race patrilineally.
Each study dates Adam differently. One says he appeared roughly 188,000 years ago. The other estimates he lived up to 49,000 years ago. But both buck the notion that modern humans emerged in disparate spots across continents. “We are finding that humans have very, very shallow genetic roots which go back very recently to one ancestor,” says the University of Arizona’s Michael Hammer, author of one of the studies. “That indicates that there was an origin in a specific location on the globe and then it spread out from there.”