by Greg Mayer
A couple of news items from the past month deserve a quick comment or two. First, at the American Association for the Advancement of Science annual meeting in Chicago last month, Svante Paabo of the Max Planck Institute announced the completion of a draft genome for Neanderthal man, and that it indicated that modern man and Neanderthal man did not interbreed: the Neanderthals are our evolutionary cousins, not members of our own species. The work by Paabo on the Neanderthal genome, and on ancient DNA in general, is fabulous, but two caveats must be noted: the first draft covers only 63% of the genome; and, most of the DNA comes from one cave in Croatia. So what you can say is in the 63% of the DNA they’ve looked at there’s no sign of interbreeding at this location. But we know secondary contact of differentiated populations in ice age Europe can be very complex; e.g. hooded crows would show evidence of interbreeding with carrion crows if sampled in some places but not others, so the case isn’t closed. And a personal quibble: according to the BBC
The draft genome can give us clues to the genetic regions which make us “uniquely human”, Prof Paabo told BBC News.
Besides the usual need to realize that knowing the genome of “X” doesn’t mean we know what it is that makes “X” so “X-ian”, Paabo implies here that Neanderthals weren’t human. But by any biologically coherent notion of human they were (hence Homo neanderthalensis). John Hawks (hat tip: Pharyngula) has an excellent discussion of all sorts of issues relating to the Neanderthal genome.
Second, John Long (who has a wonderful book on fish evolution) and two colleagues published a paper in Nature (abstract only) reporting internal fertilization and vivipary in a placoderm, a group of ancient fish. This is a wonderful discovery, showing again that Philip Skell doesn’t know what he’s talking about (Skell, you’ll recall, had said fossils “cannot reveal the details that made these amazing living organisms function”!!!). But the paper got twisted in media reports into these fish inventing sex. The BBC headline said “Fish fossil clue to origin of sex“, while, even more inexcusably, the British Museum (Natural History) website had “Fish knew first about sex“. Sexual reproduction originated in bacteria, probably billions of years before these fish. These fish may be the earliest vertebrates with copulation with an intromittent organ (a penis or similar structure); such organs have evolved multiple times, including four times in the amniotes (reptiles, birds, mammals). The price of journalism is eternal vigilance.