TORONTO, CANADA--More than 5000 experts met here from 26 to 30 October for the annual meeting of the American Society of Human Genetics. Longevity, milk digestion, and cancer were among the topics. By some estimates, less than half of all adults can easily digest milk, a trait believed to have first appeared in people who kept dairy animals. Now scientists have traced the genetic roots of milk tolerance to the Ural mountains of western Russia, well north of where pastoralism is thought to have begun. The surprising result may support a theory that nomads from the Urals were one of...