Phylogenetic and molecular analyses suggest sex-determining mechanisms can evolve quite rapidly in this group [ Janzen and Krenz, ; Organ and Janes, ; Ezaz et al. Alternative splicing: Multiple control mechanisms and involvement in human disease.
Second, by waiting for the discovery of bona fide sex-determining genes in mammals, we limit the rate of discovery of candidate sex-determining genes in reptiles. PLOS Biology. Read Our th Anniversary Issue. Integrative and Comparative Biology. Given the long list of genes that play a role in gonad development in mammals [ Wilhelm et al.
For example, females may benefit more than males from a warmer developmental temperature that causes the clutch of eggs to hatch earlier than normal. Here the spermatozoa all have an X chromosome; the eggs are of two kinds, some with X and others with Y….
This pattern affects the development of the organism by controlling cellular metabolism and stimulating the production of hormones that trigger the development of sexual glands or organs. Paternity assignment allowed researchers to calculate male reproductive success, which is the number of offspring from a male that survive to the next year.
What happens next?
The scope of the model for other reptiles, however, requires further research. In the bearded dragon, the exception may even be a benefit, as ZZ females lay more eggs that ZW females. Half of the eggs in each treatment received an aromatase inhibitor, which successfully produced males in all treatments.
Individuals with low levels of aromatase during the thermosensitive period will develop male characteristics.
Bergeron et al. PCBs can act as an estrogen replacement, causing feminization of sex organs in growing reptiles. We tested this hypothesis by incubating snapping turtle eggs at a temperature The sex of a reptile embryo partly results from the production of sex hormones during development, and one such process to produce those hormones depends on temperature of the embryo's environment.