We've had enough of the Lorena Bobbit jokes in the 90s amirite?! There's no need to bring that back up, even when faced with such temptation as this.
Turns out that scientists in Switzerland, while creating a mouse line with a deletion in a region important for development, got an unexpected result in their female mice.
We analyzed full-night video recordings and witnessed females chasing males assiduously. In the course of such inverse pursuits, they often bit the genitals,
very specifically, while the hind paws of the male were off the floor. Inverse pursuits involving such bites were directed at males exclusively, never at bystander females.
What the Hell are you doing ladies?! Bad mouse. Don't do that.
The strange part is, they're not otherwise aggressive except during the time they're supposed to be mating. They don't do it to other females and the males don't seem to react aggressively back, even after getting his dick chewed. What's going on?!
Don't make an MRA-style mangina joke. It's just not worth it. you can do it, stay focused.
Hox genes are believed to have no function in neuroectoderm derived cells in forebrain.
They encode transcription factors and are selectively repressed
throughout the midbrain and forebrain of all vertebrates. Remarkably, we
found ectopic expression of the Hoxd10 gene in diverse regions of the developing forebrain in Del1–9 (HoxDAfc)
newborns. Later, in adult, expression was maintained only in a few
cells in the basomedial amygdala, and a new domain of ectopic expression
appeared in the hippocampus.
Basically, a gene that is not supposed to be expressed in the developing or adult brains of these mice is expressed, which is the most likely cause for this very, very strange behaviour. Is it that the abnormal expression of the gene causes a malformation in the developing brain of some kind, or is the expression of the gene in adult females the direct cause of the behaviour?
Speculation at this point, but gawd, science can be some crazy shit.
Source: Zakany, J. and Duboule, D. (2012). A Genetic Basis for Altered Sexual Behaviour in Mutant Female Mice. Current Biology http://dx.doi.org/10.1016/j.cub.2012.06.067