The traits — thicker hair shafts, more sweat glands, characteristically identified teeth and smaller breasts — are the result of a gene mutation that occurred about 35,000 years ago, the researchers have concluded.
The discovery explains a crucial juncture in the evolution of East Asians. But the method can also be applied to some 400 other sites on the human genome. The DNA changes at these sites, researchers believe, mark the turning points in recent human evolution as the populations on each continent diverged from one another.
...Yet a third view is held by Dr. Kamberov, who believes that each of the effects of the EDAR variant may have been favored by natural selection at a different time. A series of selections on different traits thus made the variant version so common among East Asians. About 93 percent of Han Chinese carry the variant, as do about 70 percent of people in Japan and Thailand, and 60 to 90 percent of American Indians, a population descended from East Asians.
East Asian Physical Traits Linked to 35,000-Year-Old Mutation
