Environmental regulation of sex determination in reptiles vs amphibians in Port the Lincoln

The processes of primary sex differentiation are considered to involve exposure to a dose of some male-determining factor during a specific quantum of developmental time during early incubation. A 7-day pulse of one temperature on the background of another was insufficient to alter the sex ratio dramatically.

The various patterns of environmental sex determination in squamates, chelonians and crocodilians are described.

High temperatures produce males in lizards and crocodiles but females in chelonians. In particular, differentiation of the gonad at 33 degrees C was enhanced compared with 30 degrees C. A 7-day pulse of one temperature on the background of another was insufficient to alter the sex ratio dramatically.

Incubation at 33 degrees C increased the rate of growth and development of alligator embryos. Gov't Review. The phylogenetic implications of TSD for crocodilians, and reptiles in particular, are related to the life history of the animal from conception to sexual maturity.

Publication types Research Support, Non-U.

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In the s, David Crews, a biologist at the University of Texas at Austinand colleagues found that some environmental pollutants caused sex-altering effects in turtles and other reptiles. Over the next two decades, scientists worked to test mechanisms of sex differentiation in more species and to pinpoint pivotal temperatures, which are species-specific temperature ranges in which males and females are produced in equal number.

Temperature-dependent sex determination in reptiles Location-dependent sex determination in Bonellia and Crepidula. Amphibian larvae are not lethally affected, but they can carry the fungus in mouthparts and toe tips during later stages of development.

When two species of turtles were raised at female-promoting temperatures, Sox9 expression was down-regulated during the critical time for sex determination. Non-native fish may also prey upon native amphibians and reptiles. When a breeding pond dries up prior to the onset of metamorphosis, the entire reproductive effort for the year is lost.

Silber Middle East Fertility Society Journal Exploring the evolution of environmental sex determination, especially in reptiles F.

The processes of primary sex differentiation are considered to involve exposure to a dose of some male-determining factor during a specific quantum of developmental time during early incubation. Abstract The various patterns of environmental sex determination in squamates, chelonians and crocodilians are described.

Gov't Review. High temperatures produce males in lizards and crocodiles but females in chelonians. The phylogenetic implications of TSD for crocodilians, and reptiles in particular, are related to the life history of the animal from conception to sexual maturity.

Environmental regulation of sex determination in reptiles vs amphibians in Port the Lincoln

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  • Environmental regulation of sex determination in reptiles Article · Literature Review (PDF Available) in Philosophical Transactions of The Royal Society B Biological Sciences () Jun 25,  · In temperature-dependent sex determination, however, it is the environmental temperature during a critical period of embryonic development that determines whether an egg develops as male or female.
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  • Feb 01,  · APPLIED ANIMAL BEHAVIOUR SCIENCE ELSEVIER Applied Animal Behaviour Science 51 () Environmental sex determination in reptiles Claudio Ciofi a'b' *, Ian R. Swingland b a Institute of Zoology, Zoological Society of London, Regent's Park, London, NWI 4RY, UK b The Darrell Institute oj'Conseruation and Ecology, University oj'Kent, Canterbury, CT2 7PD, UK Abstract In Cited by: One of the best-studied reptiles is the European pond turtle, Emys obicularis. In laboratory studies, incubating Emys eggs at temperatures above 30°C produces all females, while temperatures below 25°C produce all-male broods. The threshold temperature (at which the sex ratio is even) is °C (Pieau et al. ).The developmental period during which sex determination occurs can be Cited by:
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  • Apr 28,  · Environmental sex determination in reptiles. Affiliations. Department of Biology, University of Chicago, Illinois, , USACited by: Abstract. In many reptiles, amphibians, and fishes, the environment plays a key role in determining the sexes of individuals. Temperature, in particular, appears to be a potent modulator of sex allocation in all three vertebrate classes, yet we do not yet know how temperature interacts with physiology in these systems to influence sexual development.
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  • May 20,  · Crocodilians and some turtles may be affected the most, because of their temperature-dependent sex determination. Altered sex ratios could affect population demographics and persistence. Reptiles and amphibians could also be affected by climate change if . Jan 01,  · Although GSD is common in reptiles, many species that have been karyotyped show no evidence of heteromorphic sex chromosomes (), presumably because homomorphic chromosomes have been retained, or have changed very little, from the ancestral state ().Nevertheless, reptiles exhibit remarkable variation in the degree of sex chromosome differentiation (Solari, ), which may .
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