Reptiles have a few different means of determining the sex of their offspring. Sex determination falls into two broad categories: Temperature-Dependent Sex Determination (TSD) and Genotypic (genetic) Sex Determination (GSD). With TSD, the incubation temperature of a clutch at an early critical stage in embryonic development determines whether the hatchlings will be all male, all female or a mixture of both. With GSD, sex chromosomes of the parent or parents determine the sex of the offspring. Crocodilians, Tuatara, and many turtles appear to have sex determined by temperature. With GSD, one parent typically carries a homogametic set of chromosomes (e.g., Female=XX), and the other carries a heterogametic set (e.g., Male=XY). How these combine determines the sex of the offspring.
This lesson is part of Certified Herpetological Guide. Enrollment is self-paced, with no deadline to finish (about 50 hours).
