s (3 individuals....that's why "Frankenstein") that were found in Croatia and date back to 38,000 ya. The preliminary and maybe most shocking(?) conclusion is.... when comparing this first Neanderthal nuclear genome draft with 5 living human genomes (from South Africa, West Africa, New Guinea, China, and Europe) Richard Green and colleagues found that the European and both Asians (Asia and Oceania samples) share 1-4% of their genomes, but... both Africans do not. Thus, the first conclusion after this is that Neanderthals interbred with anatomically modern humans (AMH) after modern humans (again, anatomically speaking) left Africa, but before spreading into Europe, Asia and Oceania. Ok, for those that took my courses (Anth 202 or 303) or probably any biological anthropology course, this new evidence suggests that Multiregional model (MRM) is alive (and some colleagues are very happy indeed). But, let's review some other information before making any big conclusions here...So far, most mitochondrial DNA (mtDNA) studies did not reveal admixture between Neanderthals and AMH (i.e. Currat and Excoffier, 2004; Serre et al, 2004) but we must agree that mtDNA can't solve by itself the interbreeding question. Now the nuclear DNA (nuDNA) is telling a different story, but not what I (we?) was expecting.... I mean, if interbreeding happened between AMH and Neanderthals, it seems that Europe should be the place. But this new study (so far) suggests that it was an earlier encounter that took place probably in Middle East (if not, how can we explain the genetic similarity with modern Asians samples....or , we should think a little further to explain that).
So, is MRM fully re-emerging here? I am not so sure about that, but it seems that the classic Out of Africa (plus replacement) model is under serious problems with this genetic evidence. But, let me bring here one of the final comments from Green et al paper: "Thus, while the Neandertal genome presents a challenge to the simplest version of an 'out of Africa' model for modern human origins, it continues to support the view that the vast majority of genetic variants that exist at appreciable frequencies outside Africa came from Africa with the spread of anatomically modern humans". Perhaps, we are moving into a new Assimilation model (AM). The first AM was proposed by F. Smith and colleagues back in 1989, and re-edited in 2005. Initially, AM sounds like MRM, but is not. As Smith and colleagues wrote five years ago: "AM differs from MRM in that AM recognizes Africa as the likely source of the basic modern human anatomical form and that the modern humans radiating out of Africa have the major, catalytic effect on the emergence moderns in Europe and Asia". Maybe (as many colleagues pointed out) the multiregional scenario for the origin of modern humans should be applied during the late Pleistocene (and not for the last 1 million years or more).
I will strongly recommend my students to read carefully the last segment on Green et al. paper, entitled: "Implications for modern human origins". It is clear that the direction of gene flow, population size (AMH and Neanderthals), population structure and population expansions are key components in this discussion; and not only genes but fossils and tools (too) will continue helping to get closer (only "get closer") to the final answer.
Finally, as everybody is asking, will it be possible to have nuclear genome information from Middle Eastern Neanderthals.... around 80,000 ya? (maybe we are asking too much). Or....it will be more useful to invest money expanding the sample for the modern human genome? (so far only 5 individuals were used in this study).
Besides the entire "interbreeding agenda", a future analysis that is emerging is the search for genes that have evolved (and fixed) recently in our genome (check Table 2 in Green et al, 2010), and this issue deserves a different debate.
Since the Neanderthal genome discussion is just starting, probably this will not be the last post about it....
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