Diversity matters

Science Daily:

Human migration from Africa to Europe more than 30,000 years ago appears to have left a mark on the genes of Europeans today.

A Cornell-led study, reported in the Feb. 21 issue of the journal Nature, compared more than 10,000 sequenced genes from 15 African-Americans and 20 European-Americans. The results suggest that European populations have proportionately more harmful variations, though it is unclear what effects these variations actually may have on the overall health of Europeans.

Computer simulations suggest that the first Europeans comprised small and less diverse populations. That would have allowed mildly harmful genetic variations within those populations to become more frequent over time, the researchers report.