Meeting Abstract

2.11  Jan. 4  Do yolk steroids influence sex in a species with temperature-dependent sex determination? PAITZ, Ryan T.*; HEIDENREICH, Byron A.; BOWDEN, Rachel M.; Illinois State University; Illinois State University; Illionis State University rpaitz@ilstu.edu

Maternally derived yolk steroids can affect numerous offspring phenotypes in oviparous species. Many studies in reptiles have demonstrated a critical role for steroids in sex determination, but whether or not steroids of maternal origin affect sex determination has yet to be clearly illustrated. If yolk steroids affect sex determination, their respective receptors must be present early in development. Several studies have detected sex specific steroid levels in the brain prior to their presence in the gonads, indicating that the brain may be important in the sex determination process. We characterized yolk steroid levels across development and preformed immunocytochemistry (ICC) in the brains of developing red-eared slider (Trachemys scripta) embryos to characterize estrogen receptor development. Clutches were incubated at either male (26�C) or female (31�C) producing temperatures and sampled every five days. Initial work conducted at a female producing temperature demonstrates that yolk steroid content declines dramatically prior to day 15 of development coincident with the presence of estrogen receptors in the brain. In this study we, compare the pattern of yolk steroid decline and estrogen receptor development in both sexes. Characterizing yolk steroid levels and steroid receptor patterns during development is critical in determining if maternally derived yolk steroids play a role in sex determination.