New findings could help unravel that mystery. In a scientific paper published online today by the journal Nature, researchers report having discovered an important difference between the human variant of a language-linked gene known as FOXP2 and the versions found in our great ape kin. Sequencing of the DNA encoding the FOXP2 protein in the chimpanzee, gorilla, orangutan, rhesus macaque, mouse and human reveal that the human FOXP2 contains unique changes in the DNA's amino acid building blocks. This and other evidence, say study authors Svante Pbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues, "strongly suggest that this gene has been the target of selection during recent human evolution."
The investigators speculate that the changes evident in human FOXP2 may account for our ability to exert fine control over movements of the mouth and larynx--a talent that the great apes lack. If so, and if, as the team's estimates suggest, the variant became established in the human population during the last 200,000 years of human history--roughly the time at which anatomically modern humans arose--the gift of gab may have been a driving force in their expansion.