Thursday, May 18, 2006

Who's Your Daddy?

Who's your Daddy?

Well, judging from the latest issue of Nature, he wasn't a Neanderthal. But he might have been a chimpanzee.

This is going to drive certain religious folk who are stuck in the 14th century absolutely nuts. Scientists around the world are using new and inventive DNA sequencing techniques to extract lineage information from long-dead skulls and other bones which they can then compare with live animals like us. One result appears to be the discovery that our distant human relatives interbred with a lot of chimpanzees.

Or, as Michael Hopkins puts it more delicately in the latest news from Nature magazine [subscription required]:
The evolutionary split between humans and our nearest evolutionary cousins, chimpanzees, may have occurred more recently than we thought, according to a new comparison of the respective genetic sequences. What's more, it might have been a messy divorce rather than a clean break — leading to the controversial theory that our two sets of ancestors may have interbred many thousands of years after first parting company.

* * *
[R]esearchers led by David Reich of Harvard Medical School in Boston, Massachusetts, now calculate that the split [between Humans and Chimpanzees] may have occurred no more than 6.3 million years ago, and possibly as recently as 5.4 million.
One consequence of the findings is that new doubt has been cast on the exact nature of the Toumai skull, found five years ago. It's been asserted by some that Toumai was the earliest hominid remains yet found, while others claimed it looked more like a chimpanzee. Without more bones, no one could be sure.

The latest DNA sequencing, however, leaves Toumai out of the bipedal human category altogether.
But that doesn't mean she wasn't your grandmother.

Even after diverging from chimps, it now appears that humans and chimpanzees continued to have a... shall we say, intimate relationship.

Another Nature article this week, this one by Rex Dalton, reports on DNA sequencing being done at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. He reports that a new technique for extracting genetic fragments from ancient bones suggests the "Neanderthal Y chromosome is substantially more different from human and chimp Y chromosomes than are other chromosomes."

This would mean that humans engaged in "little interbreeding... at least among the more recent Neanderthal species."

Some will put two and two together and see this as great news. Homo Sapiens had little or nothing to do with the brutish-looking Neanderthals. But others will see it as bad news: Our human ancestors preferred the affections of chimpanzees.

We suspect both views are far too anthromomorphic. Isn't it just as likely that it was the Neanderthals who wouldn't have anything to do with us, rather than the other way 'round?

This makes perfect sense to us. Especially if the Neanderthals caught us cavorting with chimpanzees.

Luckily for those of us who are around today, the chimps were less persnickety about who they slept with.

No comments: