Neanderthals and humans got fiddly

The big news this week in evolution is of course the sequencing of the Neanderthal genome, and the evidence that humans carry some DNA from our extinct cousins. The paper was published in Science yesterday, and has a total of 56 authors, including team leader Svante Pääbo. The abstract reads

Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the Neandertal genome to the genomes of five present-day humans from different parts of the world identify a number of genomic regions that may have been affected by positive selection in ancestral modern humans, including genes involved in metabolism and in cognitive and skeletal development. We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.

The blogosphere has been all over this fascinating news: Jerry Coyne (for the illustration) and Carl Zimmer (with lots of background), Iddo Friedberg, and Christie Wilcox.

Usually such newsworthy research gets one article in Science Daily, but this time there are four:

Neandertal Genome Sequence Published in Science

Complete Neanderthal Genome Sequenced: DNA Signatures Found in Present-Day Europeans and Asians, but Not in Africans

Neanderthal Genome Yields Insights Into Human Evolution and Evidence of Interbreeding With Modern Humans

Neandertals 'Hardly Differed at All' from Modern Humans

Evidence now suggests that humans not only lived side by side with Neanderthals, but also had sex with them, and that that led to offspring that lived in the human population. But I already knew that, because one of my Danish friends has so big Neanderthalic brow ridges that he can rest a bottle of (cold) beer on his forehead if he leans back a little. Neat trick in the summer heat that must have been under positive selection.

But seriously, for me the really interesting thing about this possibility is that it suggests that Neanderthals contributed something really valuable to human DNA. Genes affecting metabolism, cognitive abilities, and our skeletons. We may speculate that these contributions even made it possible for humans to invade northern Europe with its colder weather, or gave us some other advantage that led to humans taking over the niche previously occupied by Neanderthals. Perhaps it was the sex that made it all possible.

Reference:
Green RE, Krause J, Briggs AW, Maricic T, Stenzel U, Kircher M, Patterson N, Li H, Zhai W, Fritz MH, Hansen NF, Durand EY, Malaspinas AS, Jensen JD, Marques-Bonet T, Alkan C, Prüfer K, Meyer M, Burbano HA, Good JM, Schultz R, Aximu-Petri A, Butthof A, Höber B, Höffner B, Siegemund M, Weihmann A, Nusbaum C, Lander ES, Russ C, Novod N, Affourtit J, Egholm M, Verna C, Rudan P, Brajkovic D, Kucan Z, Gusic I, Doronichev VB, Golovanova LV, Lalueza-Fox C, de la Rasilla M, Fortea J, Rosas A, Schmitz RW, Johnson PL, Eichler EE, Falush D, Birney E, Mullikin JC, Slatkin M, Nielsen R, Kelso J, Lachmann M, Reich D, & Pääbo S (2010). A draft sequence of the Neandertal genome. Science (New York, N.Y.), 328 (5979), 710-22 PMID: 20448178