A gene important in limb development that is normally suppressed after birth can cause female mice to become sexually aggressive, biting the genitals of males, when it is anomalously expressed in the brain.

Jozsef Zakany and Denis Duboule at the University of Geneva, Switzerland, deleted a tiny section of the mouse genome that includes a cluster of developmental genes called HoxD. The deletion resulted in the abnormal expression of one Hox gene in small populations of brain cells. This caused females in the sexually receptive phase of their reproductive cycle to hyperactively chase male mice, biting the males' genitals and severely mutilating them.

The finding could open up new approaches for investigating the molecular and cellular basis of female courtship behaviour, say the researchers.

Curr. Biol. http://dx.doi.org/10.1016/j.cub.2012.06.067 (2012)