My Wisconsin genetics colleague Sean Carroll writes in the NY Times this week about hybridization. A passage on adaptive combinations in hybrids concludes with the Neandertal story:
It now appears that 1 percent to 4 percent of the DNA sequence of Europeans and Asians, but not Africans, was contributed by Neanderthals mixing with Homo sapiens, perhaps in the Middle East 50,000 to 80,000 years ago. It is possible that some Neanderthal versions of genes enabled modern humans to adapt to new climates and habitats.
This should be the new common sense, I should think. The more interesting aspect to me is whether there are non-obvious traits later populations got from Neandertals. Locally adaptive traits don't require much creativity to imagine, but what about globally adaptive ones?
Carroll notes that the estimated divergence time of humans and Neandertals is now quite low. He doesn't point out that it is much, much lower than many of the natural cases of hybridization he discusses. The population dynamics of the Late Pleistocene was not a generalized case, but imposes some clear conditions on the amount of time that either population may have been adapting to its locale, and how independent they had become. The current estimate of 1-4% interbreeding is more than enough to pick up essentially anything adaptive from the Neandertal genome.
