Using genome-wide scans, the New York Times' Nicholas Wade says that researchers are searching for evidence of recent natural selection in the human genome, adding that the recent finding that Tibetans have a set of genes that allow them to live in areas of low oxygen could "be the most recent known instance of human evolution." These studies have had a stutter-start, he says, but signals of selection may be seen in genes involved in diet and skin color and are more commonly seen in people of East