The intestines were the organ tested by the researchers, and the results they found were more than interesting. The researchers used genetic tools that allowed them to turn the expression of a gene "on" or "off," which allowed them to manipulate the femininity or masculinity of the stem cells of the intestines being observed. They found that the sex differences in intestinal stem cell behavior rely on a doublesex- and fruitless-independent branch of sex differentiation pathway downstream of transformer. These mechanisms are believed to be intrinsic mechanisms that control cell cycle duration. The researchers suggest that based on this newly observed cascade of sex differentiation, "a new sex determination pathway is at play." It should also be noted that differences between the organs were controlled for hormonal differences.
The major difference found between the masculine and feminine intestines was that the females intestines had a greater rate of proliferation. The enhanced ability of growth is believed to allow the female gut to grow during reproduction, but also makes them more prone to tumors. The enhanced rate of growth was noted by researchers to allow easier creation of genetically induced tumors. Overall, the increased plasticity of the gut is believed to make reproduction possible for the female.
This new discovery raises the question of whether or not this translates to humans, and how it can be applied to medicine. If we do discover that our organs are aware of their own sexuality, this could explain differences between men and women's health beyond the affect of differing levels of hormones. This would hopefully lead into a greater and more accurate scope of practice by health care providers. More tests will need to be done in the future on whether or not our organs have differences in sexuality, and how medicinal treatment can correspond accordingly.
Credit: MRC CSC