Found at Dienekes and GNXP:
Hui Li et al., Genetic Landscape of Eurasia and “Admixture” in Uyghurs. AJHG 2009. Now freely available at PubMed.
The interesting stuff is in figure 1:
So we have now a cluster centered at the Khanty (an East Uralic population) but strong in Central Asians that is distinct from both West and East Eurasians.
I think this is the coolest discovery of autosomal genetics in quite a long time.
Dienekes protests about the inconsistence of this with Y-DNA but I fail to see the connection, because Y-DNA or even mtDNA, surely scattered in the early Upper Paleolithic when Eurasians were still very much undifferentiated, while these components are surely shallower and represent regional homogeneization processes that happened surely only after the LGM. Also the impact of Y-DNA flows may be really weak: Buriats and Finns share Y-DNA lineage, as do Polish and many Indians or West Europeans and some Central Africans but it's obvious that these don't correlate too well with autosomal genetic clustering which has its own processes of regional homogeneization, while haploid genetics and specially Y-DNA is subject to high odds of fixation by mere drift and founder effects.
Razib says that the authors seem to be arguing for greater number of (strategically chosen?) populations, what makes total sense and has served, when done, to add many shades to the tricomy of the old HapMap continental hyper-simplification.
However it's very possible that a deeper cluster analysis would have revealed futher clusters, maybe an Indian one (very small sample though) or a distinction between the Khanty and Central Asians or...
Where does this Central Eurasian cluster stem from. I'd say, based on haploid genetics, that it was probably created by the admixture of a West Eurasian and East Eurasian migration converging in that peripheral area and then coalescing into a rather homogeneous cluster on its own right. That would explain why the population appears almost exactly intermediate between the two major continental groups and also why there is no haploid lineage that specifically belongs to that region (all are shared with either West Eurasia or East Asia).
East Asian variations
It is noticeable that three quite distinct populations emerge in East Asia: inland, coastal and south. These are probably essentially comparable with the blue, yellow and one (or all together) of the SE Asian components detected in the HUGO Consortium paper.