Silver-tongued humans may owe their language prowess to a foxy friend. A new study provides more evidence that the human version of a protein known as FOXP2 may have aided the evolution of language.
Chimpanzees and many other animals have FOXP2, but the human version differs at two links in the chain of amino acids that make up the protein. Scientists have suspected that those two amino acid changes were not merely cosmetic, but might alter the way FOXP2 functions, perhaps paving the way for the evolution of language. The new study finds that human FOXP2, compared with the chimp version, alters the activity of at least 116 genes in brain cells grown in laboratory dishes, neurogeneticist Daniel Geschwind of the University of California, Los Angeles and colleagues report in the Nov. 12 Nature.
Of the affected genes, 61 showed higher activity with human FOXP2 than the chimp form. Many of those genes are involved in neural development and the production of collagen, cartilage and soft tissues. Those results suggest that the protein may play roles in shaping both the brain and the vocal apparatus that makes speech possible. The human version of the protein decreased activity of 55 genes.
Together these findings are “consistent with these genes being part of a molecular circuit related to human cognition,” including circuits needed for language, Geschwind says. He thinks FOXP2 and the genes it regulates make the brain better able to integrate sensory information with movements, as in hearing sounds and then shaping the tongue, lips and vocal tract to reproduce those sounds.