Over at GNXP, Razib has posted a few links to papers concerning adaptive evolution (aka, positive selection or Darwinian selection) in humans and chimps. He’s been following the coverage of this paper from George Zhang’s group which provides evidence that more genes have been under positive selection along the chimpanzee lineage than the human lineage. The popular press are advertising this finding as “chimps more evolved than humans”, and Razib’s gotten a kick out of the phrasing (part 1, part 2, part 3). Zhang and colleagues interpret their finding the in framework of the nearly neutral theory, arguing that less adaptive fixations in humans are the result of a smaller ancestral population size in humans than chimps. One issue I have from a first glance is that the conclusion is reached using only divergence data. It’s unclear how many of the differences between humans and chimps are fixed and how many are polymorphic.
Razib also linked to this paper from Scott Williamson and colleagues (which includes Andy Clark, Carlos Bustamante, and Rasmus Nielsen) on identifying adaptive evolution in humans using SNP data. The authors claim that they found 101 regions of the human genome with strong evidence of selective sweeps. And there’s also this post on selection and migration in human populations.