Evolution; International Journal of Organic Evolution. Long-lasting consequences of elevated yolk testosterone levels on female reproduction. Keywords: Sex determinationReptilesTurtlesHormones. One cause of TSD is the enzyme aromatase.
Estrogen and sex reversal in turtles—a dose-dependent phenomenon. Hamlin, Russell H. Although there is evidence that sex steroids can be produced in the chorioallantoic membrane CAM of terrestrial eggs [ 4 ], maternally derived yolk steroids are believed to be the primary hormone reservoir directing embryonic development prior to gonadogenesis [ 5 ].
Daily Audio Program. Your browser does not support the audio tag. Washington: Smithsonian Books, The results, which found evidence of TSD in four out of five species, confirmed that some vertebrate species exhibit TSD. However, there is evidence that during climactic extremes, changes in the sex determining mechanism itself to GSD are selected for, particularly in the highly-mutable turtles.
How temperature determines sex in alligators. Article Navigation. For this assay, no separation of bound and free hormone is necessary because only the bound radiolabled steroid is capable of exciting the scintillant coating the bottom of the well.
Adrenal kidney and gonadal steroidogenesis during sexual-differentiation of a reptile with temperature-dependent sex determination. At oviposition, the egg yolk serves as a considerable reserve of maternally derived steroids that is available to direct early development [ 32 — 36 ].