Are Reptiles Predisposed to Temperature- Dependent Sex Determination?

  title={Are Reptiles Predisposed to Temperature- Dependent Sex Determination?},
  author={Arthur Georges and Tariq Ezaz and Alexander Quinn and Stephen D. Sarre},
  journal={Sexual Development},
  pages={7 - 15}
Vertebrates show an astonishing array of sex determining mechanisms, including male and female heterogamety, multiple sex chromosome systems, environmental sex determination, parthenogenesis and hermaphroditism. Sex determination in mammals and birds is extraordinarily conservative compared to that of reptiles, amphibians and fish. In this paper, we explore possible explanations for the diversity of sex determining modes in reptiles, and in particular, address the prevalence of reptilian… 

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A Novel Candidate Gene for Temperature-Dependent Sex Determination in the Common Snapping Turtle
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Sex Determination in Reptiles
  • J. Bull
  • Biology
    The Quarterly Review of Biology
  • 1980
Temperature-dependent sex determination (TSD) is common in turtles and has been reported in two lizards and alligators; however, data on TSD are available for few non-turtle species and an attempt is made to deduce their ancestries.
Phylogeny of sex-determining mechanisms in squamate reptiles: are sex chromosomes an evolutionary trap?
It is concluded that to date there is no known well-documented transition from GSD to TSD in reptiles, although transitions in the opposite direction are plentiful and well corroborated by cytogenetic evidence.
Genetic evidence for co-occurrence of chromosomal and thermal sex-determining systems in a lizard
This study provides direct evidence that incubation temperatures can sex-reverse genotypically female offspring, using a DNA sex marker, and hence the validity of current classification schemes for sex-determining systems in reptiles is challenged.
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The ends of a continuum: genetic and temperature‐dependent sex determination in reptiles
It is argued that genetic and environmental sex determination in reptiles should be seen as a continuum of states represented by species whose sex is determined primarily by genotype, species where Genetic and environmental mechanisms coexist and interact in lesser or greater measure to bring about sex phenotypes, and species where sex isetermined primarily by environment.
A mechanistic model of temperature-dependent sex determination in a chelonian: the European pond turtle
A new thermal model of TSD using a mechanistic approach that provides integration of incubation temperature fluctuations, as well as the cumulative and differential effect of high and low temperatures on sexual differentiation to embryo sex determination for the European pond turtle.
Temperature Sex Reversal Implies Sex Gene Dosage in a Reptile
It is shown that high incubation temperatures reverse genotypic males to phenotypic females in a lizard with ZZ and ZW sex chromosomes, suggesting that sex chromosomes may exist in many TSD reptiles.
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  • Biology
    Evolution; international journal of organic evolution
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Results from an expression study of a gene involved in early gonadogenesis in GSD (Apalone mutica) and TSD (Chrysemys picta) turtles, support the hypothesis that Wt1 in A. mutica displays such a relic thermal sensitivity.
Temperature of egg incubation determines sex in Alligator mississippiensis
Sex is fully determined at the time of hatching and naturally irreversible thereafter, and depends on the temperature of egg incubation, which constitutes a possible selective evolutionary advantage of temperature-dependent sex determination (TSD) in alligators in that females become large and sexually mature as early as possible.
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Most amphibians lack morphologically distinguishable sex chromosomes, but a number of experimental techniques have shown that amphibian sex determination is controlled genetically, and debates concerning interactions between the developing gonads and the invading germ cells, and even the origin of the medullary and cortical portions of the developing Gonad remain unresolved.