New scientific research indicates that humans and chimpanzees diverged more recently than previously thought, and that they could have been interbreeding as recently as five million years ago:

New scientific findings indicate that ancestral humans split from chimpanzee forebears more recently than previously thought and raise the possibility that the two nascent species hybridized before making their final separation.

The surprising findings reveal a much more complicated birth of the human and chimpanzee species than shown by previous research. They also call into question the place on the primate family tree of fossils that scientists had thought were the bones of ancestral humans, but which are older than the newly determined time that the species diverged.

The research, conducted by scientists at Harvard Medical School, the Massachusetts Institute of Technology (MIT), and the Broad Institute of Harvard and MIT, indicates that humans and chimpanzees developed into distinct species less than 6.3 million years ago and probably more recently than 5.4 million years ago. That is about a million years later than the previously accepted range of 6.5 million to 7.4 million years ago.

By comparing samples of chimp, gorilla and human DNA, scientists from MIT and Harvard say they see possible evidence of interspecies sex.

But there's a problem with this finding, say paleontologists who study human origins. The geneticists are proposing that our ancestors were still mixing it up with those of the chimps until six million years ago - a time when one lineage was on all fours, the other already walking upright.

And you thought your relationship had compatibility problems.

"We see a complex speciation with a long, drawn-out gene flow," said David Reich, a geneticist from Harvard Medical School and lead author of the paper, published in today's issue of the journal Nature.

Would creatures that different want to mate, let alone be able to create viable offspring? The geneticists conceded this might be a stretch, but they suggest the fossil-finders are off on the dates for upright walking. Paleontologists say the geneticists' dates are in error.

If it's any consolation, the scientists say our ancestors still behaved like apes when this alleged sex took place. We started walking upright very early after splitting off from chimpanzees, and only much later acquired large brains, complex tool use and language.

At least if my great-75,000th-grandfather was screwing a cute little chimp who walked on all fours, I can content myself with the knowledge that his brain was small.

I discussed the possibility of human-chimpanzee hybridization in a previous post. The legal and moral implications are disturbing enough that the Harvard researchers can only hint about, um doing it:

Reich cautioned that though hybridization would answer several questions raised by the research, the research itself does not prove that hybridization occurred. Further work is needed to explore whether that happened.

Richard Dawkins has discussed some of the ethical implications:

. . . [W]hat if somebody succeeded in breeding a chimpanzee/ human hybrid? I can assert, without fear of contradiction, that the news would be earth-shattering. Bishops would bleat, lawyers would gloat in anticipation, conservative politicians would thunder; socialists wouldn't know where to put their barricades. The scientist that achieved the feat would be drummed out of politically correct common rooms; denounced in pulpit and gutter press; condemned, perhaps, by an ayatollah's fatwah. Politics would never be the same again, nor would theology, sociology psychology; or most branches of philosophy. The world that would be so shaken, by such an incidental event as a hybridisation, is a speciesist world indeed, dominated by the discontinuous mind.

Professor Dawkins is kind enough to provide a picture:

I'm wondering whether the existence of such a creature would be earthshaking out of concern for the poor creature and its precarious legal status (obviously, it would have a tough life), or whether there would be frustration with the idea that such a thing is theoretically possible.

FWIW, considering that humans and chimps have 99.4% of their DNA in common, I think it is obvious that it is possible. At least as possible (if not more so) as the beefalo or any number of difficult hybrids such as the zorse, zobra, tion, or liger.

What I'd like to know is under what theory our ethical system is threatened. Clearly, the hybridization is possible. It would, however, be a cruel thing to do to the individual, and I would not do it. But to the extent that the threat to human ethics is based on the theory that such a breeding would be impossible, I'd say the research has already disproved that theory. If man and chimp could interbreed five million years ago, it's hardly surprising that this could be duplicated today under laboratory conditions.

Hmmm....

There are people who maintain seriously that man and chimp couldn't have interbred 5 million years ago, aren't there? They'd probably assert that breeding the two today would be impossible, wouldn't they?

That alone might provide enough reason for someone to do it. I'd feel sorry for any near-human creature, bred for the purpose of winning a debate. I would hope they'd stop at the test tube stage.

At that point, they could suspend the experiment, store the embryos in liquid nitrogen, and let them "live" in eternal suspension. The appropriate ethicists could then hold a huge debate over whether they should be killed, murdered, or (worse) be born.