THURSDAY, Oct. 22 (HealthDay News) -- A gene that plays a role in human vocal development and speech has been identified by an international team of scientists.

They pinpointed the gene, which they named "tospeak," after analyzing the DNA of members of a large family with a severe vocal disorder, which included altered composition of the vocal cords and a malformed voice box.

The scientists said the most exciting findings were that the tospeak gene is unique to primates and that the gene has a special control region, known as a promoter, that's only found in humans.

The study was scheduled to be presented at the American Society of Human Genetics annual meeting, Oct. 20 to 24 in Honolulu.

"The discovery that a unique and more powerful human gene/promoter was disrupted in this vocally impaired family is of particular interest to the field of evolutionary genetics, since humans are the only creatures that have developed the capacity to speak," the research team's leader, Raymond Clarke, principal scientific officer at St. George Clinical School of Medicine at the University of New South Wales in Sydney, Australia, said in a news release from the society.

"Tospeak is a very large gene found in primates that overlaps two other neighboring genes," Clarke said. "While we still don't know exactly how these genes function, we believe that these three genes probably act together to influence human vocal development through the regulation of gene transcription, the biochemical composition of the vocal cords and the anatomical structure of the voice box, which underlie the human capacity for speech."

He added that research is under way "to determine exactly how tospeak functions in regulating the human capacity for speech."

SOURCE: American Society of Human Genetics, news release, Oct. 22, 2009

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