If you could take a close look at your genetic profile, you would discover something that might surprise you says Jonathan Pritchard of the University of Chicago Department of Human Genetics. "Our species is not a static organism that has been the same for tens of thousands of years, but we continue to change and evolve to new conditions."
Pritchard and colleagues analyzed newly available genetic data from 209 unrelated individuals from East Asia, Europe and Africa.
Their study revealed widespread evidence of biological adaptation across the human genome in response to changes in climate conditions, new habitats and population densities over the last 5,000 to 10,000 years. "For example, in Europeans we see five different genes that play a role in skin coloring, and it seems likely that these signals are reflecting the adaptation of Europeans to more northerly latitudes as they spread north and were getting less sunlight," he says. "Light skin pigmentation is believed to be important for metabolizing Vitamin D, which protects against rickets."
Strong evidence of recent human evolution was found in genes that control the sense of smell, taste, and digestion, including the lactose gene, which enables adults to digest milk. Prichard links the start of dairy farming with this genetic adaptation. "This mutation is spread extremely rapidly under the force of natural selection, so that now virtually all Europeans and members of some other populations worldwide have mutations on the lactose gene that will allow them to digest milk." Prichard says his team will continue to search the human genome for clues to explain the ongoing phenomenon of gene adaptation.