Poppa was a rolling gene complex

Poppa was a rolling gene complex ››: Eswaran and coworkers believe they have reconciled a lot of the oddities of the genetic data for human population expansion in the Pleistocene. Here's the abstract in its entirety (with my emphasis added):

Ten years ago, evidence from genetics gave strong support to the "recent Africa origin" view of the evolution of modern humans, which posits that Homo sapiens arose as a new species in Africa and subsequently spread, leading to the extinction of other archaic human species. Subsequent data from the nuclear genome not only fail to support this model, they do not support any simple model of human demographic history. In this paper, we study a process in which the modern human phenotype originates in Africa and then advances across the world by local demic diffusion, hybridization, and natural selection. While the multiregional model of human origins posits a number of independent single locus selective sweeps, and the "out of Africa" model posits a sweep of a new species, we study the intermediate case of a phenotypic sweep. Numerical simulations of this process replicate many of the seemingly contradictory features of the genetic data, and suggest that as much as 80% of nuclear loci have assimilated genetic material from non-African archaic humans.

The problem with the longstanding data is this: some loci look like they've been replaced e.g. mitochondria while others look like they've accumulate diversity either in deep time or through admixture between archaic and modern humans. The "Out of Africa" group label the first as illustrative and the second as artefactual; the "Multiregional Hypothesis" crowd emphasize contrariwise. It'll be interesting to see how this goes down: the field is not one for having unacrimonious exchanges and group hugs, and Stringer and Wolpoff's comments will be worth watching out for. But if these researchers are right you can forget those romantic notions of your brave, as-human-as-you ancestors stalking out of Africa and taking over (perhaps suffering something devastating en route that drops their numbers waaay down but--hey!--they bounce back because they're your ancestors, right?). You can similarly discard your views that your particular race emerged in your particular corner of the world and we just happen to be one species because a few frisky and cosmopolitan types used to do the long treks between us. No, your ancestors came from all over but an advantageous gene complex emerged from Africa fairly recently and got into everybody's genomes via good old-fashioned loving-thy-neighbour. Most of you is local (meaning also out of Africa but way, way back) but what makes you a modern as opposed to archaic human came out of Africa in the last thousand centuries or so. (via) [NB: fulltext preprint is self-archived on co-author Harpending's website]. Postscript: let's not attribute too much originality to this work, which is strongly dependent on Alan Templeton's "Out Of Africa Again And Again" hypothesis (Nature 2002 doi:10.1038/416045a); [Permalink…24-May-05…Deserving memes……Comments (0)]

Poppa was a rolling gene complex

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