Literaturdatenbank
Literaturdatenbank |
|
 |
|
Crews, D. (2003). Sex determination: where environment and genetics meet. Evolution and Development, 5(1), 50.
Added by: Admin (14 Aug 2008 20:35:26 UTC) |
| Resource type: Journal Article BibTeX citation key: Crews2003 View all bibliographic details  |
Categories: General Keywords: Echsen = saurians, Panzerechsen = crocodilia, Schildkröten = turtles + tortoises, Zeitigung = incubation Creators: Crews Collection: Evolution and Development |
Views: 3/539
Views index: 9% Popularity index: 2.25% |
| Abstract |
|
In mammals and birds the genetic constitution established at the time of fertilization determines the type of gonad that develops, whereas in all crocodilians and many turtles it is the temperature experienced during the mid-trimester of embryogenesis that initiates gonadal differentiation. Research with the red-eared slider suggests considerable conservation in the genetic cascades that underlie the sex determination process in vertebrates and, further, that the patterns of expression of these genes appear to reflect phylogenetic relationships, with turtles being more similar to mammals than they are to birds and crocodilians. After the determination and differentiation of an individual's gonadal sex, epigenetic forces shape those morphological, physiological, and behavioral traits that characterize each individual's unique sexuality. Research with the leopard gecko thus relates to the fundamental question of what factors determine individual variability, particularly as it relates to sexually dimorphic behaviors. Taken together, this research illustrates how sexuality depends on sex, but sex should not be confused with sexuality. That is, sex is merely a means of categorizing individuals or gonads, whereas sexuality serves as a descriptor of concordant traits each of which is typically sexually dimorphic in its expression.
Added by: Admin |