all Catherine Dulac stories

Sensory organ differentiates male/female behavior in some mammals

50443248 — Mon, 01 Oct 2007 16:50:40 -0400

For years, scientists have searched in vain for slivers of the brain that might drive the dramatic differences between male and female behavior. Now biologists at Harvard University say these efforts may have fallen flat because such differences may not arise in the brain at all.

Rather, they say, the epicenter of sex-specific behavior in many species may be a small sensory organ found in the noses of all terrestrial vertebrates except higher primates. Their work, appearing this week in the journal Nature, indicates that defects in this 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.

Sexual attraction a matter of scent

70652986 — Mon, 26 Mar 2007 05:42:13 -0400

An unexpected finding may settle an ongoing scientific debate by providing evidence that key reproductive behaviors in mice arise predominantly, if not exclusively, from olfactory input instead of input from the vomeronasal, visual, or auditory senses.

The results, from a team led by Harvard biologist Catherine Dulac, appear on the Web site of the journal Cell and were published in the journal's Nov. 18, 2005 issue.

"It's always interesting when there is a surprise finding," says Dulac, professor of molecular and cellular biology in Harvard's Faculty of Arts and Sciences and an investigator with the Howard Hughes Medical Institute. "Most biology textbooks now say that pheromones affecting reproductive behavior in nonhuman mammals are detected by the vomeronasal organ, while the nose processes all other odors. Our work suggests quite convincingly that the mouse nose processes both pheromones and other scents, and in fact provides much or all of the chemosensory input that drives mating."

In addition to funding from the Howard Hughes Medical Institute, the research was supported by the National Institutes of Health.

Sexual ID switch is found

70652986 — Mon, 26 Mar 2007 05:19:03 -0400

A gene named TRP2 (pronounced "Trip 2") produces a signaling protein that regulates both aggression and sexual behavior in male mice. Male mice can, of course, distinguish other males from females by their looks, size, and smell. But a Harvard research team, led by Catherine Dulac in the Department of Molecular and Cellular Biology. found that with TRP2 switched off, no matter what their senses tell them, male mice will not fight for their territory, and they will make love to male intruders as quickly as they will to females. "We are totally surprised that a single gene has such a profound effect on behavior," admits Dulac. "In humans, such basic behaviors are unlikely to be explained by the activity of only one gene.