Temperature dependent sex determination in sea turtles

Marinković, Mija (2010) Temperature dependent sex determination in sea turtles. Bachelor's thesis, Faculty of Science > Department of Biology.

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Abstract

Sex determination is controlled either by genetic or environmental factors. In many reptiles, gonadal sex is determined by the incubation temperature of the egg, a process known as temperature-dependent sex determination (TSD). Reptiles with TSD exhibit various relationships between temperature and sex ratio. Low temperatures produce females and high temperatures produce males in many lizards and crocodilians, whereas this pattern is reversed in most turtles. Estrogen playes a significant role in sex determination in reptiles with TSD. Some genes of the mammalian sex-determining pathway have been identified in gonads of different vertebrates. Sox9, Dax1 and Dmrt1 are expressed at the onset of gonadal development in birds and reptiles. Today we are still unclear as to how temperature ultimately effects the sex of the embryo, but the argument for the role of estrogen appears even stronger. Some of the effects of toxicants such as polychlorinated biphenyls (PCBs) can have estrogenic effects and can induce reproductive anomalies. There is abundant evidence that manmade products can become environmental toxicants.

Item Type: Thesis (Bachelor's thesis)
Supervisor: Lacković Venturin, Gordana
Date: 2010
Number of Pages: 20
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Silvana Šehić
Date Deposited: 04 Dec 2014 11:25
Last Modified: 04 Dec 2014 11:25
URI: http://digre.pmf.unizg.hr/id/eprint/3453

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