Faster Human Evolution
By Arnold Kling
Tyler Cowen talks about a new scientific paper. He quotes from the UK Telegraph.
Prof Hawks says: “We are more different genetically from people living 5,000 years ago than they were different from Neanderthals.”
Naturally, our friends at Gene Expressions are on top of this one. Razib writes,
One can think of “per locus error rate” [p] as basically mutation rate. [N is the size of the population.] The paper suggests that Np = 1 is a major threshold , below this point stochastic effects are powerful and the ambient rate of mutation is a major parameter shaping adaptive evolution (not neutral evolution, which is not dependent on population size). When Np > 1 stochastic effects are less salient and selection is powerful enough to swamp random deviation so that it can drive beneficial mutations to fixation.
…This summer I had lunch with some economists and they kept talking about the idea that as human population increases the number of innovations would increase and so the frontier of the rate economic growth would naturally expand outward in value. Ultimately Nature is One, and insights and logic which bear fruit in one branch of science may be more relevant than we thought across the whole arc of creation.
Another GNXP blogger, p-ter , writes skeptically,
is the statistical power to detect alleles of different ages identical? If the test has low power to detect old sweeps and good power to detect recent ones, there you go– an artefactual acceleration. There is little discussion of these parameters in the original paper and less here. Don’t get me wrong– the areas of the genome they identify as selected are almost certainly enriched for true selective events, but how enriched? These questions are perhaps less important in a first-pass scan for selection, but if you’re going to make generalizations about selected sites, they’re essential. The claim in the paper that “demographic causes of extensive LD can be discriminated easily from those caused by adaptive selection” is not demonstrated (and is false)
I tried to explain the concept of statistical power to my high school students yesterday, and near the end of class they asked why it was important. I hope I can use this example as an answer, without having to explain (which in turn would require that I understand) the biology .