Monday, April 10, 2006

The Lactose Intolerant Are Genetically Inferior

Speedy Evolution
"The time scale for a strongly favored mutation to sweep through a population is about 5,000 years," said Jonathan Pritchard, a University of Chicago evolutionary biologist. "It's hard to get an exact estimate for rates of change, but we know that the lactase gene is evolving the fastest in humans. It was new 5,000 years ago and now it's in virtually everybody in Europe."

The lactase gene is what allows humans to metabolize dairy products as adults. It's widely believed to have evolved in response to humans' domestication of dairy animals -- individuals who could enhance their diet with dairy products had such a strong survival advantage that the gene spread at the speed of, well, several thousand generations.


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