Thursday, November 16, 2006
Two posts on my other blog, I try to show with pictures my own idea of the "3 models" of human origins, Multi-regionalism, Out of Africa, and the new model which Greg & John haven't christened yet. In another post I try to offer up when I see as the essence of the difference between Multi-regionalism and the new model (which I provisionally label "Ecotype Persistence").
John got so many hits today that he had to go on back up servers, but keep watching that space! There must have been a lot of querying for Neandertals today, I started getting referrals from this six month old post over at MSNBC about the topic because they linked to me!
Long time readers of the blog will note that the characterization of the Ecotype Persistence model is simply a glorified version of Henry Harpending's "Racial Diversity" post from the early years of this blog. In Race: the Reality of Human Differences Vincent Sarich marvels at human variation, and offers that selection must be powerful indeed to reshape a species as young as our own into so many different morphs. But Ecotype Persistence offers a way for us to ratchet down the god-like powers of selection, Sarich assumed that the variation in our species was a function of mutation from 50 K BP to the present as well as the extant genetic variation of the ancient African population. For such diversity to pop up with little raw material to work with clearly one would assume that selection is working 24-7 like a Korean clerk. But the extant genetic variation that might be available for local positive selection driven by ecological pressures might be orders of magnitude greater than Sarich assumed because novel alleles did not have exist in the African genetic background or emerge de novo. Modern humans could have "picked them up" through isolated interbreeding events and quickly shape-shifted to somewhat resemble the archaic homonids whom they were demographically marginalizing!
Addendum: Why do we assume Neandertals were hairy?