Last week, Current Biology released an article about structural differences between sexes in Drosophila melanogaster. It may not be about a human brain, but it’s still neurology and at least semi-related to developmental biology this time.
While the “model” organism displays distinct behavioral differences between sexes, the overall anatomy in regards to dimorphism has been essentially neglected. Previously, the only discernible difference was in the olfactory system. Male olfactory systems have a 25 – 60% larger volume than female flies. Coincidently the male pheromone cVA attracts females while repelling males (however no credible correlation can be made).
Pretty picture! This is one of many from a collage presented in the article and most interesting to myself as it visibly shows the gender difference in brain size. Magenta is larger in females and green is larger in males.
The article proceeds to explain the fine tunings of specific proteins (fruitless, sex lethal, and transformer) and their effect on dimorphism in a manner that is, quite frankly, far beyond my level of comprehension.
Overall, sexual dimorphism does exist in the Drosophila brain and may influence behavior as a result. A key example of this lies in the activation of fruM (the male version of the fruitless protein) in females and the resulting behavior of courting other females. Now that the anatomical groundwork has been laid the researchers are able to pursue behavioral consequences in future research.