Natural selection still happening in humans
No big surprise here, but a new paper in PLOS-Biology did a search for signs of positive selection in the human genome and turned up several genes in different populations that have been selected for very recently.
Providing the strongest evidence yet that humans are still evolving, researchers have detected some 700 regions of the human genome where genes appear to have been reshaped by natural selection, a principal force of evolution, within the last 5,000 to 15,000 years.Some readers may recall that a few months ago I noted a study showing that certain alleles of two genes involved in determining brain size had undergone strong positive selection in the recent past in Europeans and Asians but not Africans, leading certain people to embrace the finding as suggesting that Africans are genetically determined to have low IQs. I wonder how they will react to the finding in this study that another gene involved in determining brain size, CDK5RAP2, shows signs of selection in the Yoruba of Nigeria, but not Europeans or East Asians? (A different brain size gene, CENPJ, was selected for in Europeans and Asians.)
The genes that show this evolutionary change include some responsible for the senses of taste and smell, digestion, bone structure, skin color and brain function.
Many of these instances of selection may reflect the pressures that came to bear as people abandoned their hunting and gathering way of life for settlement and agriculture, a transition well under way in Europe and East Asia some 5,000 years ago. ...
Three populations were studied, Africans, East Asians and Europeans. In each, a mostly different set of genes had been favored by natural selection. The selected genes, which affect skin color, hair texture and bone structure, may underlie the present-day differences in racial appearance.
PS, I was amused by the picture accompanying the NYTimes article - it's as though the photographer was desperate to get the standard picture of the biologist in the white lab coat gazing thoughtfully at a test tube full of purple liquid, but had to settle for equations with a population geneticist.