The ancestors of humans and chimpanzees may have interbred and exchanged significant numbers of genes after the initial split between the species, scientist report in the May17th online edition of Nature
Chimpanzees and humans officially split up along the evolutionary path up to ten million years ago, but it seems they may have continued having sex with one another for a good four million years after that.
A detailed analysis of human and chimp DNA suggests the lines finally diverged less than 5.4 million years ago.
The finding, published in the journal Nature, is about 1-2 million years later than the fossils have indicated.
Commenting on the research, Daniel Lieberman, a professor of biological anthropology at Harvard, told the Associated Press: "It's a totally cool and extremely clever analysis.
"My problem is imagining what it would be like to have a bipedal hominid and a chimpanzee viewing each other as appropriate mates, not to put it too crudely."
From BBC
I'll let you make you own jokes for this one