Charnier observed that temperature affected sex ratios, which are the number of females versus males in a population or a single clutch of eggs, of the rainbow Agama lizard, Agama agama. Bibcode : PLoSO Integrative and Comparative Biology. Nicole Valenzuela and Valentine Lance, 21—
Sunderland, Mass. Temperature pulses during the thermosensitive period are often sufficient to determine sex, but after the TSP, sex is unresponsive to temperature. Molecular Phylogenetics and Evolution 43 : — Bradypodion ventrale was missing in the chamaeleonid phylogeny, therefore, we estimated its position from the topology of B.
Often-debated questions concern the evolution and phylogeny of individual sex-determining mechanisms and the possibilities of reciprocal shifts between them. Sign Up. In contrast, squamates lizards and snakes and turtles exhibit both genotypic sex determination and temperature-dependent sex determination, although temperature dependence is much more common in turtles than in squamates.
For the references and detailed list of taxa see Supporting Information Table S1. NCBI Bookshelf.
Sensitive stages for the effects of temperature on gonadal aromatase activity in embryos of the marine turtle Dermochelys coriacea. Bonellia viridisa marine worm, has location-dependent sex determination; sex depends on where the larvae land. Developmental biology 8th ed. Also, experiments conducted at the pivotal temperature, where temperature is equivocal in its influence, have demonstrated an underlying genetic predisposition to be one sex or the other.
Download as PDF Printable version. Aromatase CYP19which regulates gonadal estrogen levels, is proposed to be the main target of a putative thermosensitive factor for TSD. Recent Activity.
Recent Activity. Bull, James, and Richard Vogt. Front Genet , , 07 Aug These chemicals block the conversion of testosterone to estradiol during development so each sex offspring can be produced at all temperatures. PCBs can act as an estrogen replacement, causing feminization of sex organs in growing reptiles.
Bibcode : PLoSO