Temperature-dependent sex determination in reptiles: proximate mechanisms, ultimate outcomes, and practical applications
| Autor: | Thane Wibbels, James J. Bull, Judith M. Bergeron, James K. Skipper, Alan Tousignant, Deborah Flores, David Crews |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
medicine.medical_specialty Sex Differentiation medicine.drug_class Offspring medicine.medical_treatment Molecular Sequence Data Biology Sex hormone-binding globulin Internal medicine Genetics medicine Animals Humans Amino Acid Sequence Sexual differentiation Temperature-dependent sex determination Aromatase Inhibitors Temperature Reptiles Estrogens Cell Biology Androgen biology.organism_classification Cell biology Turtles Steroid hormone Endocrinology Receptors Estrogen Leopard gecko biology.protein Androgens Female Oxidoreductases Developmental Biology Hormone |
| Zdroj: | Developmental genetics. 15(3) |
| ISSN: | 0192-253X |
| Popis: | In many egg-laying reptiles, the incubation temperature of the egg determines the sex of the offspring, a process known as temperature-dependent sex determination (TSD). In TSD sex determination is an "all or none" process and intersexes are rarely formed. How is the external signal of temperature transduced into a genetic signal that determines gonadal sex and channels sexual development? Studies with the red-eared slider turtle have focused on the physiological, biochemical, and molecular cascades initiated by the temperature signal. Both male and female development are active processes--rather than the organized/default system characteristic of vertebrates with genotypic sex determination--that require simultaneous activation and suppression of testis- and ovary-determining cascades for normal sex determination. It appears that temperature accomplishes this end by acting on genes encoding for steroidogenic enzymes and steroid hormone receptors and modifying the endocrine microenvironment in the embryo. The temperature experienced in development also has long-term functional outcomes in addition to sex determination. Research with the leopard gecko indicates that incubation temperature as well as steroid hormones serve as organizers in shaping the adult phenotype, with temperature modulating sex hormone action in sexual differentiation. Finally, practical applications of this research have emerged for the conservation and restoration of endangered egg-laying reptiles as well as the embryonic development of reptiles as biomarkers to monitor the estrogenic effects of common environmental contaminants. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text