Meeting Abstract
Temperature dependent sex determination (TSD) is exhibited by many organisms and is particularly common in reptiles. In this system, the temperature of the developing embryo determines its sex through complex pathways which still are not fully understood. Recent research has revealed that the isolated bipotential gonad is capable of sensing temperature and directing differentiation into an ovary or testis in vitro in several organisms exhibiting TSD. However, estrogen signaling also plays a critical role in TSD and exposure to 17β-estradiol (E2) in ovo during the thermosensitive period (TSP) of development results in sex reversal at male-producing temperature (MPT) in species including the American alligator, Alligator mississippiensis. At the tissue level, E2 exposure has been shown to significantly alter sexually-dimorphic gene expression in isolated cultured gonads from the red-eared slider turtle. However, the concentration needed for this effect of exogenous E2-mediated sex reversal in vitro on the isolated gonad-adrenal-mesonephric (GAM) complex in A. mississippiensis is not known. Thus, GAM complexes were isolated from embryos one day prior to TSP and exposed to varying concentrations of E2 or vehicle alone while held at a male-producing temperature in culture for 1-2 weeks. Gonadal sex of the cultured GAMs will be assessed by analyzing sexually dimorphic mRNA abundances such as aromatase and anti-Müllerian hormone via quantitative PCR. These results will provide important additional insight into the role of E2 in sex determination in organisms exhibiting TSD.
