Meeting Abstract

P1.91  Wednesday, Jan. 4  Using sexually dimorphic gene expression in scutes as a marker of sex in the American alligator UNDERWOOD, E.B.*; KOHNO, S.; RAINWATER, T.R.; BOGGS, A.S.P; DOHENY, B.; MCCOY, J.; GUILLETTE, L.J.; College of Charleston, Charleston; Hollings Marine Laboratory, Charleston; MUSC, Charleston; Hollings Marine Laboratory, Charleston; Hollings Marine Laboratory, Charleston; MUSC, Charleston; MUSC, Charleston; MUSC, Charleston; MUSC, Charleston; Hollings Marine Laboratory, Charleston elunderwood@davidson.edu

The increasing levels of environmental contaminants are cause for concern as they have deleterious,irreversible impacts on ecosystems around the globe. One group of contaminants, endocrine disrupting chemicals(EDCs),are important as they can affect an organism’s reproduction and development. In species that undergo temperature dependent sex determination,such as the American alligator,EDCs can cause sex reversal during development. This change in sex determination could potentially skew sex ratios within a population,consequently impacting the entire ecosystem. Thus,it is important to be able to monitor sex ratios in American alligator populations in a non invasive or minimally invasive way. Currently,no way exists to determine the sex of hatchlings. This study explores cadidate genes expressed in a sexually dimorphic pattern in scute samples taken from adult alligators from the Yawkey Wildlife Preserve,Georgetown,SC. RNA was isolated from 24 different scute samples (12 males and 12 females). Quantitative RT-PCR was conducted using 5 candidate genes (ESR1,ESR2,AR,CYP19,and StAR) to quantify mRNA expression. We detected all 5 mRNAs in the alligator scutes,however no single gene was expressed in a sexually dimorphic pattern. These results indicate that the scute could have a steroidogenic function and receive sex steroid signals. Moreover,our data suggest this tissue could also be disrupted by EDCs.