More Cheerful Facts about Neanderthals:
There has been a flurry of articles about the Neanderthal people. (Close Encounters of the Prehistoric Kind, SCIENCE vol. 328 no. 5979 May 7, 2010 page 680 and in the same issue A Draft of the Neandertal Genome Richard E. Green et al page 710; A Cave Man Blinking in the Light, ECONOMIST vol. 397 no. 8681 May 8, 2010 page 79; Ancient DNA Set to Rewrite Human History, NATURE vol. 465 no. 7297 May 13, 2010 page 148; Did Neandertals Think Like Us? SCIENTIFIC AMERICAN vol. 302 no. 6 June 2010 page 72.) The occasion has been that a draft of the genome of the Neanderthal has now been published. Surprises abound.
The first surprise is that something I had said earlier now turns out not to be true. I had thought it had been established that Neanderthals and modern humans had never interbred, or at least that there were no surviving genes from such a cross. That puzzled me a bit. Neanderthals had red hair, which tends to be a European trait, and they were last seen in Europe. That seemed a bit of a coincidence. Another European trait appears to be women’s rights. And I thought maybe modern human women might have liked being treated nicely, if that’s what Neanderthals did.
Wrong on both counts. I should have known better.
As it turns out, the decision that humans carried no Neanderthal DNA had been based on comparing mitochondria, little organelles in the cell that mediated energy transfers. They are a small fraction of the DNA, most of it being in the nucleus. (Hence the “N” in DNA.) And they are only passed from mother to son or daughter, never from the father. Well the nuclear DNA of most humans does have a couple of a percent of Neanderthal origin. So maybe the ladies liked them after all. But the inter mating appears to have occurred in the Holy Land. (That area does keep cropping up.) From there the Neanderthal – modern human cross expanded across Eurasia and obviously to the western hemisphere as well. So there is nothing about red hair, women’s rights or anything else one might imagine to be European that in fact goes back to Neanderthals in Europe.
It seems that the only places to have no Neanderthal input are in Africa. They are the last of the pure strain modern humans. The proportion of Neanderthal DNA appears to be constant throughout Eurasia, so that population must have expanded out of a single highly successful community.
And of course the cross mating occurred where modern humans and Neanderthals first came together rather than where they were last known to be together. A long time passed in between. The longer two populations are separated the less likely fertile crosses are.
So I am covered with rue. Sorry. I hope you didn’t wager the barn on that one.
There are several pictures of what people imagine Neanderthals to have looked like in the articles. I swear that I look more like a Neanderthal myself than at least one of them.
Another interesting point to consider is whether they went extinct. If their DNA survives, then in a sense they never did. So some of the new pictures look rather smug. I suppose modern humans, well entrenched in Africa, greatly outnumbered the Neanderthals when contact was made. If they outnumbered them say 100 to 1, then you could make a case that the crossing preserved more Neanderthals than it preserved modern humans. They won. Darn. Who would have guessed? I think it is pretty clear at this point that there is more Neanderthal DNA in the world today than there was when they ruled Eurasia alone. So let’s hear it for cross breeding, eh what?
And a final point has been brought up. It has long been known that Stone Age humans in Europe were highly sophisticated artists. I couldn’t match some of those cave paintings even after some training in commercial art. It generally has been thought that Neanderthals were no artists, and anything that looked good from that time had to be modern human work. Then things began to show up that made it pretty clear that Neanderthals were doing art, too. So it was assumed that they were copying modern humans. But modern humans hadn’t done anything of the sort before they came to Europe. So it has been seriously suggested that maybe “we” were copying “them.” (“We” and “them” get a bit muddled now that it seems we are a bit of both.)
So there is much excitement in the field. Personally I think at this point more information will be forthcoming and I have resolved never again to have an opinion about Neanderthals. Then maybe I won’t have to write another retraction.
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