Oct. 28, 2009 -- Culture, not just genes, can drive evolutionary outcomes, according to a study released Wednesday that compares individualist and group-oriented societies across the globe.

Bridging a rarely-crossed border between natural and social sciences, the study looks at the interplay across 29 countries of two sets of data, one genetic and the other cultural.

The researchers found that most people in countries widely described as collectivist have a specific mutation within a gene regulating the transport of serotonin, a neurochemical known to profoundly affect mood.

In China and other east Asian nations, for example, up to 80 percent of the population carry this so-called "short" allele, or variant, of a stretch of DNA known as 5-HTTLPR.

Earlier research has shown the S allele to be strongly linked with a range of negative emotions, including anxiety and depression.

Critically, it is also associated with the impulse to stay out of harm's way.

By contrast, in countries of European origin that prize self-expression and the pursuit of individual over group goals, the long or "L" allele dominates, with only 40 percent of people carrying the "S" variant.

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The study, published in Britain's Proceedings of the Royal Society B: Biological Sciences, offers a novel explanation as to how this divergence might have come about.