Meeting Abstract
In marine turtles, sex is determined based on the environmental factors that an embryo experiences during incubation, in particular temperature. The pattern of temperature-dependent sex determination (TSD) is hot female, cool male. Because sex determination in turtles is so closely linked to environmental conditions, the most common prediction associated with climate change is that marine turtles will be at a higher risk of extinction if sex ratios become dramatically female-biased. These concerns highlight the importance of identifying current and historical sex ratios at sea turtle nesting beaches. Estimating hatchling sex ratios at rookeries remains imprecise due to the lack of sexual dimorphism in young marine turtles and delayed sexual maturity. Most common practices for estimating sex ratios are indirect, based on nest temperatures, air and sea surface temperatures, incubation duration and estimated thermosensitive period durations. However, there is insufficient evidence that these proxies indeed result in realistic primary sex ratios from natural sea turtle nests or rookeries. The lack of a simple, nonlethal technique to verify the sex of hatchlings is at the foundation of this problem. The purpose of this study was to develop a technique to identify sex in loggerhead sea turtle (Caretta caretta) hatchlings via analysis of blood samples. We used Western blots to detect the expression of several proteins known to play an important role in sex differentiation in hatchling blood samples. The presence of these proteins were then compared to the results from laparoscopic or histological procedures in order to validate this approach. Finding a sex-specific marker in hatchling turtle blood samples would allow for large scale measurements and verification of naturally occurring sea turtle sex ratios; a crucial step in assessing the impacts of climate change on turtle demographics.
