From Tina Hesman Saey, “Helpful Mutations Didn’t Sweep Through Early Humans”, Wired Science (February 18, 2011) we learn
Humans probably didn’t get swept up in evolution.Scientists have favored a model of evolution in which beneficial gene mutations quickly and dramatically sweep through a population due to the evolutionary advantages they confer. Such mutations would become nearly universal in a population. But this selective sweep model may not be accurate for humans, a new study indicates. Human evolution likely followed a more subtle and complicated path, say population geneticists Molly Przeworski of the University of Chicago and Guy Sella of Hebrew University of Jerusalem and colleagues.
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Good evidence does exist for some mutations that did undergo selective sweeps in humans, such as those for skin pigmentation, hair and teeth morphology and the genetic change that allows adults in some populations to digest the milk sugar lactose. But those examples are the exception rather than the rule in human evolution.
About the milk sugar lactose: I thought it depended on whether you were raised with the stuff (or practically drowned in it, as some of us were), and lots of semi-drowned people get lactose intolerance late in life. Heck, the local grocery’s dairy case offers a number of lactose-free products I am glad I do not need to sample.
Of course, the authors offer the usual homage to Darwin’s natural selection as being true anyway: it is happening somewhere else. In “some fruit flies.”
That’s either “Hold broadcast. This just in” or “Yawn. The usual application of Darwinate” ( opaque protective coating for counter-Darwin evidence).