ORIGINS: A Gene for Speech

Linguists have long been fascinated by a London extended family with a rare hereditary speech disorder. Half the 30 family members have a genetic mutation that makes clear speech impossible. Although normal in other respects, they can't pronounce complex words like hippopotamus and don't use connecting terms like or and if. Researchers isolated the responsible gene last year and dubbed it FOXP2. Now comes tantalizing evidence that FOXP2 may have played a role in the evolution of modern humans.

By comparing DNA from humans, chimpanzees and other animals, researchers from the Max Planck Institute in Leipzig, Germany, and the University of Oxford in England determined that FOXP2 hardly changed during the evolution of mammals. But their analysis, reported last week in Nature, indicated a subtle genetic shift in the human family tree within the past 200,000 years. "The gene seems to trigger the development of the ability to move the mouth, lips and tongue as well as certain neural processes," says Wolfgang Enard, one of the study's German authors.

In theory, at least, the findings explain why primates other than humans can't speak. They also suggest that improved communication allowed early modern humans to expand across the globe.