The researchers, who published their findings in the March 31, 2004, issue of the Journal of Neuroscience, said that their finding will aid research on how genes contribute to the architecture and function of brain circuitry for singing in birds.
Among the lead researchers was neurobiologist Erich Jarvis, Ph.D., of Duke University Medical Center and Constance Scharff of the Max Planck Institute for Molecular Genetics in Germany. Co-first authors of the paper were Sebastian Haesler of the Max Planck Institute and Kazuhiro Wada, M.D., of Duke. Other authors were Edward Morrissey of the University of Pennsylvania and Thierry Lints of the City College of New York. The work was supported by the U.S. National Science Foundation and the German Research Foundation.
According to Jarvis, the search for the gene, called FoxP2, began when other researchers reported that the human version of the gene was responsible for a deficit in language production in humans.
"In affected humans, the mutation causes a very specific dysfunction," said Jarvis. "These people have largely normal motor coordination, but an inability to correctly pronounce words or form them into grammatically correct sentences. What's more, they have trouble understanding complex language."
When evolutionary geneticists compared the DNA sequence of the normal human FoxP2 gene with nonhuman primates and other species, they found that humans have a specific sequence variation not found in any other mammal, said Jarvis.
"Thus, since birdsong is a learned vocal behavior like speech, we decided to find out if a version with this same variation was present in vocal-learning birds," said Jarvis.