The concept of an archaic introgression is a late compromise between classical Multiregionalism and Out-of-Africa. Classical Multiregionalism postulated independent modernization in Europe, Africa and Asia with regionally specific technological and biological continuity traits (e.g., shovel-shaped incisors and facial flatness in Asians and in Homo erectus, Mousterian-to-Aurignacian lithic continuities in Europe), with subsequent gene flow and cultural diffusion across the three continents that resulted in the sharing of biological and cultural features that we call “common humanity.” But you’re right that it’s possible that Denisovians are Homo erectus.

Weirdo racists on some other websites claim that archaic admixture mean that Eurasians are more evolutionarily advanced relative to Africans yet at the same time archaic admixture means that Melanesians are more evolutionarily primitive than Eurasians! Which one is it? It can’t be both.

It is a vindication in that modern humans are an admixture of AMH and archiac species, and that the admixture level (at least in the case of Denisovians) is not uniform for all contemporary humans. Certainly, specific multiregional predictions are wrong. But, the concept of introgression of archaic humans into modern humans was apparently right, and it is entirely possible that the Denisovians were Homo erectus or a direct successor to Homo erectus.

“There seems to be some selective advantage that begins at the base of L and was retained on up through all the various divisions of M and N, so that no pre-L mitochondria now exists.”

Also note that no pre-M or pre-N exist in Africa. Neither there are any L lineages found at small receding frequencies outside of Africa. All M and N lineages found in Africa (M1, U6, etc.) are derived from outside of Africa. There are several mutation steps separating M and N from L3 that haven’t spawned separate lineages. Biogeographically, too, there’s no continuity between Africa and Europe or Asia in terms of phylogenetically deeper M and N nodes being closer to Africa than phylogenetically more recent ones. This is explained sometimes as the result of a fast migration along the coast with subsequent diversification in South and Southeast Asia, but this scenario, again, doesn’t explain why there are no African lineages outside of Africa and why there was no stepwise differentiation in Africa prior to the migration of M and N out. The whole out of Africa scenario is a very mechanistic model that relies on several unproven assumptions.

“We have only really started looking at diversity”: fantastic! We’re studying DIVERSITY and so we can’t be criticised politically.

We have only really started looking at diversity, and there will be some more surprises on the way.

Strictly speaking the mtDNA evidence is incompatible with recent Out of Africa and is compatible with the multiple archaic scenario

” For mtDNA, a TMRCA of 170,000 years is within the range of values predicted by the `Multiple Archaic Populations’ scenario (P(TMRCA less than 170,000) = 0.21), but the mitochondrial TMRCA estimate is diffi cult to reconcile with the remaining three scenarios (P less than 4×10-2). “

No way would I play rugby against Samoans, Fijians or Maori. Physically they are in a different league.

But Papuans are built much smaller.

Napolioni Nalaga reminds me a little of the greatest Rugby player ever IMO, the outstanding Jonah Lomu, who at 6′ 5″ and 260 Lbs, was also super fast – this clips shows him swatting other rugby players like flies as he sprint home with the ball.

http://en.wikipedia.org/wiki/File:Napolioni_Nalaga.jpg

Good point. Now not only do we have serial bottlenecks on the way out of Africa (at least two major ones: for all non-Africans and for Amerindians), which kept reducing the original levels of diversity, but also serial archaic admixture effects (for all non-Africans and for Melanesians), which keep increasing the depleted levels of diversity. Now we just need a couple of Toba-like events to throw into the mix and we’re good to go into 2011.

Absolutely agree. And at the “nuclear insert” (Zischler et al. 2005), too, that proved to be the closest to the Mungo man sequence. The insert and the Mungo man sequence are re-visited here. http://rokus01.wordpress.com/2010/03/27/denisova-cave-and-the-mystery-of-the-mtdna-phylogenetic-tree/#comment-349

Also, notably the frequencies of the insert parallel the frequencies of “archaic admixture” in humans: high outside of Africa, low in Africa.

It seemed to me that canids as cursorial social carnivores provided an interesting analogy for population history in humans. If the eastern wolf Canis Lycaon could act as conduit for genes from the coyote Canis latrans into the gray wolf Canis Lupus it seemed to me that the model of a perfect cladistic tree splitting but never coming back together would likely not work in human lineage either. Its very exciting to see similar results coming out now in humans. At that time wolves were considered one holarctic species expect the controversial canis lycoan, now we see evidence for distinct populations in the Himalayans and india that have been seperate for hundreds of thousands of years. This kind of cryptic population structure seems like it to might be a good model for Pleistocene population dynamics in humans with much of the structure from that period wiped out by later demic expansion leaving just tantalizing hints like this.

I do think given the controversy over mutation rates the most parsimonious explanation is still that Denisova is simpy an asian erectus, and the reason we do not see its genetic signature in other asian population is that it was pushed into south east asia during the last glacial maximum and encountered modern humans there. Still I would not be surprised at all to find out once again things are more complicated.

How can it be a vindication for Multiregionalism? Multiregionalists claimed that Neanderthals have a special connection to modern Europeans. Ancient DNA study refutes it time and again. Multiregionalists couldn’t dream of Denisovians. Ancient DNA identified them as a new hominid population. There’s no evidence so far of any introgression of Homo erectus genes into modern humans. The fact that ancient DNA refutes out-of-Africa, too, doesn’t mean it supports the other camp. Both camps are wrong.