The thermosensitive, or temperature-sensitive, period TSP is the period during development when sex is irreversibly determined. There is only a small range of temperatures that permits both males and females to hatch from the same brood of eggs.
In this species, high incubation temperature during egg development reverses genotypic males ZZ into phenotypic females; so females can be ZZ or ZW, but males are always ZZ.
Turtle species that display TSD are thought to follow one of two patterns of temperature dependence. Bull, James. Here again, evolution provided the answer. At certain levels of PCBs, the feminizing effects can override the influence of temperature, negating the effects of TSD in an organism.
Blocking the activity of Stat3 led to activation of the male-specific pathway, even at elevated temperatures. And as climate change begins to alter the temperatures of turtle habitats, understanding this pathway could potentially inform conservation approaches.
It is not known whether the temperature sensitivity resides in the aromatase gene or protein itself or in other proteins that regulate it. Sex Chromosomes and Sex-Linked Genes. Temperature-dependent aromatase activity is also seen in diamondback terrapins, and its inhibition masculinizes their gonads Jeyasuria et al.
New Jersey: Prentice Hall, Copy to Clipboard Reference Copied to Clipboard. One of the best-studied reptiles is the European pond turtle, Emys obicularis. However, there is no evidence thus far that sex ratio is manipulated by parental care. In most species, gender is determined during fertilization.
Adaptation of sea turtles to climate change is vital so that thermal tolerance is increased to prevent issues such as imbalanced sex ratios, abnormal offspring development and low hatching success caused by high incubation temperatures in sea turtle populations Miller,