Meeting Abstract
The red-eared slider turtle ( Trachemys scripta elegans ), exhibits temperature-dependent sex determination, where sex-specific genes are produced in response to incubation temperature. Cold-inducible RNA-binding protein ( Cirp ) is a candidate gene in the sex-determining pathway as previous research has demonstrated sex-specific Cirp expression in several species of turtles. However, prior studies have used constant incubation temperatures, which fail to capture the thermal variability that developing embryos would naturally experience. We compared patterns of Cirp expression in the gonads of T. s. elegans embryos exposed to a simulated heatwave during a period when developing gonads are sensitive to thermal cues. Eggs were incubated for 24 days at male-producing temperatures (25.0 ± 3 °C) before a subset were shifted to female-producing temperatures (29.5 ± 3 °C). Embryos were then sampled from both the male-producing and female-producing conditions for six consecutive days. In contrast to results from constant temperature studies, we found that Cirp expression did not differ between the fluctuating male-producing and female-producing temperatures. These findings highlight the importance of using ecologically relevant conditions when evaluating gene expression. Although Cirp did not vary under thermal fluctuations, we have submitted a subset of our samples for RNAseq to identify other genes that are responsive to fluctuating thermal regimes. A de novo assembly will be used to determine differential expression of male- and female-producing genes, allowing us to identify temperature-responsive candidates that are expressed during gonadal differentiation.
