The association between Foxp2 and language was first identified in a family in which half the members had severe speech and grammar impairments. Studies showed that all the affected family members had a mutation in the Foxp2 gene. The gene is found on a region of chromosome 7 that is linked to other disorders that affect speech, including autism and specific language impairment (a broad diagnosis used to describe communication difficulties in the absence of mental retardation, hearing loss, or emotional disorders).

In the study, the team engineered mice with either one or both disrupted copies of Foxp2 in order to examine the role of this gene in social communication. These are the first mice to be engineered with this particular genetic defect.

Disruption of Foxp2 affected the ability of infant rodents to emit ultrasonic vocalizations (USVs) when separated from their mother and littermates, according to the study leader, Joseph D. Buxbaum, PhD, Associate Professor of Psychiatry, of Neuroscience, and of Geriatrics and Adult Development at Mount Sinai.

Mice with two disrupted copies of Foxp2 had a complete absence of USVs, while mice with one disrupted gene emitted USVs at a significantly reduced rate. Mice with two disrupted copies of the gene also displayed severe motor skill impairment and premature death, while single-copy mice had more modest, but still noticeable, developmental delays.

"Our findings demonstrate that Foxp2 subsumes communication across species, and, as a result, we can legitimately use the mouse to learn about the neurobiology of human speech and articulation," says Dr. Buxbaum, whose paper was published on-line this week in the Proceedings of the National Academy of Sciences.

While Foxp2 disruption affected USVs, it did not appear to influe
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21-Jun-2005