Sep. 14, 2004 One of the most comprehensive studies of the
forces that have shaped patterns of human genetic variation has
found strong evidence for the action of natural selection, which
may help explain why certain people are at risk for a variety of
conditions and others are not. The findings were published
online this week for the journal Public Library of Science
Biology in a paper titled "Population History and Natural
Selection Shape Patterns of Genetic Variation in 132 Genes." For
the paper, researchers studied the molecular evolution of 132
genes by comprehensively resequencing them in 24 African-
Americans and 23 European-Americans. The results showed strong
evidence for natural selection at eight genes in the European-
American population, likely explained by the different
environmental conditions people encountered as they moved into
Europe sometime between 25,000 to 50,000 years ago. "Our results
suggest that the migration of humans out of Africa into new
environments was accompanied by genetic ada