PRESTOPUNDIT

Reporting in the cover article in Wednesday's issue of the journal Cell, Lahn and his colleagues, Eric Vallender and Steve Dorus, found that 17 brain-building genes mutated at a tremendously rapid rate in humans, compared with the brains of chimpanzees, macaque monkeys, rats and mice.

In a species that was social and cooperative but had few other survival skills, being smarter meant a lot to early humans, Lahn said. Genetic mutations that enhanced intelligence amid the pressure to survive were quickly passed on to future generations. Those not possessing the new genes eventually died off. Once started, the selection of brain-building genes snowballed, resulting in thousands of changes to thousands of genes in a relatively short period, Lahn explained.