Temperature-dependent sex determination in the American alligator: expression of SF1, WT1 and DAX1 during gonadogenesis

Western, Patrick; Harry, Jenny L.; Graves, Jennifer A. Marshall; Sinclair, Andrew H.

doi:10.1016/s0378-1119(99)00466-7

Cited by 101 publications

(86 citation statements)

References 32 publications

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“…In mammals (mouse), SF1 expression declines in the female but is maintained in the male, which is the more steroidogenically active sex. It is interesting to note that the sexually dimorphic pattern of SF1 expression seen in developing chicken gonads is similar to that reported in alligators, (58) the closest living relatives to birds. Thus, SF1 appears to have a conserved role during early gonad formation in vertebrates, but a somewhat divergent role during later sexual differentiation.…”

Section: Conserved Genes Within the Pathwaysupporting

confidence: 78%

Sex determination: insights from the chicken

2004

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SummaryNot all vertebrates share the familiar system of XX:XY sex determination seen in mammals. In the chicken and other birds, sex is determined by a ZZ:ZW sex chromosome system. Gonadal development in the chicken has provided insights into the molecular genetics of vertebrate sex determination and how it has evolved. Such comparative studies show that vertebrate sex-determining pathways comprise both conserved and divergent elements. The chicken embryo resembles lower vertebrates in that estrogens play a central role in gonadal sex differentiation. However, several genes shown to be critical for mammalian sex determination are also expressed in the chicken, but their expression patterns differ, indicating functional plasticity. While the genetic trigger for sex determination in birds remains unknown, some promising candidate genes have recently emerged. The Z-linked gene, DMRT1, supports the Z-dosage model of avian sex determination. Two novel W-linked genes, ASW and FET1, represent candidate female determinants.

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Section: Conserved Genes Within the Pathwaysupporting

confidence: 78%

Sex determination: insights from the chicken

2004

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“…In birds and reptiles, the conversion of androgenic steroids to oestrogenic steroids is regulated by the aromatase gene, the transcription of which may be activated by the SF1 gene or repressed by the AMH gene. (53) This process acts to shift the endocrine balance between male and female differentiation in the developing embryo. (39)(40)(41) Extraordinary conservatism across vertebrate orders in the genes involved in sexual differentiation, and the clear potential for some of these conserved genes to be involved in sexual determination, suggests that differences at the molecular level among reptiles with different sex-determining mechanisms might be small, potentially involving a few or perhaps only one gene.…”

Section: Sex-related Gene Expression In Reptiles and Mammalsmentioning

confidence: 99%

The ends of a continuum: genetic and temperature‐dependent sex determination in reptiles

Sarre¹,

Georges²,

Quinn³

2004

BioEssays

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Two prevailing paradigms explain the diversity of sex‐determining modes in reptiles. Many researchers, particularly those who study reptiles, consider genetic and environmental sex‐determining mechanisms to be fundamentally different, and that one can be demonstrated experimentally to the exclusion of the other. Other researchers, principally those who take a broader taxonomic perspective, argue that no clear boundaries exist between them. Indeed, we argue 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 is determined primarily by environment. To do otherwise limits the scope of investigations into the transition between the two and reduces opportunities to use studies of reptiles to advance understanding of vertebrate sex determination generally. BioEssays 26:639–645, 2004. © 2004 Wiley Periodicals, Inc.

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“…As in testis development, a number of these genes, including Wnt4, Dax1, and FoxL2, show similar patterns of expression during ovarian development in several vertebrate taxa (Smith et al, 1999b;Torres-Maldonando et al, 2002;Western et al, 2000;Loffler et al, 2003). This suggests that an ovarian pathway, complementary to the testisdetermining pathway, is conserved among vertebrates.…”

Section: Case Study: Sex Determination and Gonadal Differentiationmentioning

confidence: 85%

“…For example, in mice, Sox9 is expressed in pre-Sertoli cells following Sry expression and is required for Mis up-regulation (Koopman, 2001). Sox9 is also expressed in a male-specific manner during the period of sex determination in birds and reptiles (Western et al, 1999(Western et al, , 2000Torres-Maldonando et al, 2002;Oreal et al, 1998Oreal et al, , 2002Smith et al, 1999a). Taken together this suggests that Sox9 plays a central and conserved role in vertebrate sex determination.…”

Section: Case Study: Sex Determination and Gonadal Differentiationmentioning

confidence: 97%

From gene networks underlying sex determination and gonadal differentiation to the development of neural networks regulating sociosexual behavior

et al. 2006

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Genes are not expressed in isolation any more than social behavior has meaning outside of society. Both are in dynamic flux with the immediate environment that the gene/individual finds itself, which in turn establishes the timing, pattern, and conditions of expression. This means that complex behaviors and their genetic underpinnings should be viewed as a cumulative process, or as the result of experiences up to that point in time and, at the same time, as setting the stage for what will follow. The evidence indicates that as experiences accumulate throughout life, early experiences shape how genes/individuals will respond to later experiences, whereas later experiences modify the effects of these earlier experiences. A method of graphically representing and analyzing change in gene and neural networks is presented. Results from several animal model systems will be described to illustrate these methods. First, we will consider the phenomenon of temperature-dependent sex determination in reptiles. We will illustrate how the experience of a particular temperature during a sensitive period of embryogenesis sculpts not only the patterns of expression of genes involved in sex determination and gonadal differentiation but also the morphological, physiological, neuroendocrine, and behavioral traits of the adult phenotype. The second model system concerns the effects of the sex ratio in the litter in rats, and the genotype ratio in the litter of transgenic mice, on the nature and frequency of maternal care and how this in turn influences the patterns of activation of identified neural circuits subserving the offspring's sociosexual behavior when it is an adult.

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Temperature-dependent sex determination in the American alligator: expression of SF1, WT1 and DAX1 during gonadogenesis

Cited by 101 publications

References 32 publications

Sex determination: insights from the chicken

Sex determination: insights from the chicken

The ends of a continuum: genetic and temperature‐dependent sex determination in reptiles

From gene networks underlying sex determination and gonadal differentiation to the development of neural networks regulating sociosexual behavior

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