Saturday, July 22, 2006

He Ain't A Chimp, Sir. He's my cousin.

Friday's Wall Street Journal featured an article about the ongoing efforts to sequence the Neanderthal genome:
The Neanderthal genome project was unveiled yesterday in a news conference held at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Institute scientists plan to complete the project in two years in collaboration with the American biotechnology company 454 Life Sciences, a subsidiary of the Branford, Conn.-based CuraGen Corp. 454 has developed a speedy new approach to studying DNA.

Knowing more about Neanderthal's genes should give scientists a new window into human evolution. "The Neanderthal will be like modern humans in most ways, but more like a chimpanzee in others," said Svante Pääbo, the Max Planck geneticist who will head the effort.

Most scientists believe modern humans and Neanderthals come from a common ancestor but diverged about 500,000 years ago. Neanderthal was a heavy-boned hominid who was adapted to cold, made use of stone tools, and thrived in Europe and Asia until about 30,000 years ago.
Neanderthals are an interesting topic, both scientifically and in a wider human sense, in that they appear to have been our closest non-ancestral relatives in the Homo genus. There is, apparently, controversy about exactly how to classify Neanderthals. I had recalled reading that they were classified as a sub-species of our own species (they were classified as Homo sapiens neanderthalensis, while we are Homo sapiens sapiens) but glancing around at some current information on the web, it looks like classifying them as a separatspecieses (Homo neanderthalensis). This may be because the current understanding is that both we and the Neanderthals separately descended from Homo erectus.

One of the intriguing things about Neanderthals (both in a general and in a speculatively religious sense) is the question of whether or not we would recognize them as human. Much scientific speculation (and so far as I know there's little more than speculation on this point) centers around whether Neanderthals were capable of abstract thought, and whether they posses complex language skills. They did fashion tools (as did earlier hominids back to aprox 2 million years ago) but their tools were much simpler than those made by homo sapiens. There is also some evidence of ritual burials with artifacts, which many anthropologists consider to be evidence of a religious sense. All of which is interesting, of course, but non of which can answer the (probably unanswerable question) general question, "Where they 'human' in an essential sense?" and the more specifically religious one: "Did they have souls?"

One thing that mildly annoyed me about the WSJ article, however, was its several times repeatecuriosityty about which parts of the Neanderthal genome would prove to be similar to humans, and which would be 'more like chimps'. I'm certainly open to correction from the more knowledgeable, but I'm not clear why one would consider Neanderthals to be more similar to chimps than we are. Both Homo sapiens and Neanderthals are believed to be descended from a single common ancestor, Homo erectus. Given that, although modern humans and Neanderthals clearly would have had genetic differences, neither one would be 'closer' to chimps than the other, since the ancestral line of both split from chimps at the same time. Neanderthals might be genetically more similar to chimps in some ways, but more different in others -- but it seems like if we are both 'sibling' species descended from Homo erectus, that we'd be roughly equally distant from our 'cousins' the chimps. The "how far from chimps" line of thinking seems to spring from the "humans are descendants of chimps" line of thinking rather than the far more correct "humans and chimps share a common ancestor".

1 comment:

  1. Kinda makes one want to bang one's head against the keyboard, doesn't it?

    I tend not to get into too much of a lather with fundamentalists over evolution not only because (a) being in the South, I would have to become a hermit, and (b) I tend to think they're pretty on the ball on many other issues, but also because this sort of silliness from an educated source that should know better forces me to conclude that the fundamentalists are only part of the problem!

    There are a number of very nice hominid family trees available online, should you decide that somebody needs to have a picture drawn.

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