While sex hormones have been observed to be influenced by temperature, thus potentially altering sexual phenotypes, specific genes in the gonadal differentiation pathway display temperature influenced expression.
NCBI Bookshelf. Unlike the situation in mammals, sex determination in reptiles and birds is hormone-dependent. However, using hormonal manipulations, Warner and Shine were able to produce males at temperatures that would naturally produce females, and vice versa.
They did so to test the predictions of the Charnov-Bull model.
Access through your institution. Vertebrate Life. As ofsixty-five of seventy-nine tested species of turtles were found to exhibit TSD. They did so to test the predictions of the Charnov-Bull model. Electronic supplementary material. From Wikipedia, the free encyclopedia.
References 1 Fisher, R. Developmental Dynamics.
Their study validated the Charnov-Bull model, showing that for some species and taxonomic groups, differential fitness may be a primary force in the evolution of TSD. One of the best-studied reptiles is the European pond turtle, Emys obicularis.
The next phase can be either male or female, depending on the animal's position in the mound.
Global Change Biology. New Jersey: Pearson Education, However, in the bipotential gonads of those turtles raised at male-promoting temperatures, Sox9 expression was retained in the medullary sex cords destined to become Sertoli cells Spotila et al. Second, researchers had to develop methods to measure reproductive success for species with TSD.
Get smart. To manipulate this process, Warner and Shine administered an aromatase inhibitor to half of their developing Jacky Dragon eggs to counteract the feminizing effects of temperature and to ensure that the treated eggs would become male, even at temperatures that normally produced females.