The unbearable thinness of Denisovan

A new paper in PNAS, Archaic human ancestry in East Asia: "These results suggest admixture between Denisovans or a Denisova-related population and the ancestors of East Asians, and that the history of anatomically modern and archaic humans might be more complex than previously proposed." It's open access, so do go read it. John Hawks has a long rumination. My main thought is that I'm starting to think that people are squeezing this orange too much. I wouldn't be surprised if the broad conclusions here are correct, and in fact I'd lean in that direction. But is the discovery of relatively trace ancestry all that earthshaking? The reality is that a little over a year ago the interpretative framework of science in this area shifted. That was because of the concreteness of ancient DNA, which allowed for a direct comparison, instead of statistical sifting through the genomes of extant populations. Remember, before 2010 there were plenty of papers utilizing subtle statistics and computational muscle which "proved" and "confirmed" an Out-of-Africa with replacement model. The power and precision of these techniques tended to overshadow the reality of a margin of error, and uncertainty in their conclusions. We need to be cautious when the machinery turns itself in the opposite direction, gleaning glimpses of what we now know is likely there....