DNA study shows it was messy when humans and chimps parted ways - Yahoo! News: "NEW YORK (AP) - Humans and chimps diverged from a single ancestral population through a complex process that took four million years, according to a new study comparing DNA from the two species.
By analyzing about 800 times more DNA than previous studies of the human-chimp split, researchers from the Broad Institute of MIT and Harvard were able to learn not just when, but a little bit about how the sister species arose.
'For the first time we're able to see the details written out in the DNA,' said Eric Lander, founding director of the Broad Institute. 'What they tell us at the least is that the human-chimp speciation was very unusual.'
The researchers hypothesize that an ancestral ape species split into two isolated populations about 10 million years ago, then got back together after a few thousand millennia. At that time the two groups, though somewhat genetically different, would have mated to form a third, hybrid population. That population could have interbred with one or both of its parent populations. Then, at some point after 6.3 million years ago, two distinct lines arose."