Scientists find origin of gender behavior

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CAMBRIDGE, Mass., Aug. 7 (UPI) -- A U.S. study suggests a sensory organ, not the brain, is responsible for differentiating male and female behavior in some mammals.

Harvard University biologists have determined the epicenter of sex-specific behavior in many species might be a small sensory organ found in the noses of all terrestrial vertebrates except higher primates. The research indicates defects in that organ, known as the vomeronasal organ, lead female mice to adopt male behaviors such as mounting and pelvic thrusting while abandoning female behaviors such as nesting and nursing.

"These results are flabbergasting," Professor Catherine Dulac said. "Nobody had imagined that a simple mutation like this could induce females to behave so thoroughly like males."

The scientists said their findings do not apply directly to humans, which lack a vomeronasal organ.

Dulac, Tali Kimchi and Jennings Xu studied female mice with a mutant TRPC2, an ion channel whose absence disables the vomeronasal organ. They found the females engaged in typically male courtship activity and behaviors.

Dulac and colleagues are now studying the behavior of male mice with a mutant TRPC2 to determine whether they display female-like traits.

The research is reported in the journal Nature.