Temperature of egg incubation determines sex in Alligator mississippiensis

Ferguson, M. W. J.; Joanen, Ted

doi:10.1038/296850a0

Cited by 351 publications

(180 citation statements)

References 11 publications

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“…There is an almost haphazard distribution of TSD across the reptile phylogeny, with sister taxa at all levels exhibiting alternate modes of sex determination. At the level of order, crocodilians have TSD, (54) whereas their sister taxon, the birds, do not. At the level of suborder, snakes have GSD with a ZW chromosome sex-determining system whereas lizards exhibit many forms of sex determination including TSD.…”

Section: Transition Between Gsd and Tsdmentioning

confidence: 99%

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

Sarre¹,

Georges²,

Quinn³

2004

BioEssays

275

259

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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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Section: Transition Between Gsd and Tsdmentioning

confidence: 99%

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

Sarre¹,

Georges²,

Quinn³

2004

BioEssays

275

259

View full text Add to dashboard Cite

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“…TSD is shown by the tuatara (Cree et al, 1995), all crocodilians (Ferguson and Joanen, 1982;Deeming, 2004), many turtles (Bull and Vogt, 1979;Pieau, 1982;Ewert et al, 2004) and a minority of lizards (Charnier, 1966;Harlow, 2004). Female heterogametic GSD (ZZ males/ZW females) is apparently ubiquitous in snakes (Beçak et al, 1964;Ohno, 1967;Matsubara et al, 2006) whereas turtles and lizards with GSD have either female or male heterogamety (XY males/XX females), in some cases with multiple sex chromosomes (Solari, 1994).…”

Section: Introductionmentioning

confidence: 99%

Extension, single-locus conversion and physical mapping of sex chromosome sequences identify the Z microchromosome and pseudo-autosomal region in a dragon lizard, Pogona vitticeps

et al. 2009

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Distribution of temperature-dependent sex determination (TSD) and genotypic sex determination (GSD) across the phylogeny of dragon lizards implies multiple independent origins of at least one, and probably both, modes of sex determination. Female Pogona vitticeps are the heterogametic sex, but ZZ individuals reverse to a female phenotype at high incubation temperatures. We used reiterated genome walking to extend Z and W chromosome-linked amplified fragment length polymorphism (AFLP) markers, and fluorescence in situ hybridization for physical mapping. One extended fragment hybridized to both W and Z microchromosomes, identifying the Z microchromosome for the first time, and a second hybridized to the centromere of all microchromosomes. W-linked sequences were converted to a single-locus PCR sexing assay. P. vitticeps sex chromosome sequences also shared homology with several other Australian dragons. Further physical mapping and isolation of sex-specific bacterial artificial chromosome clones will provide insight into the evolution of sex determination and sex chromosomes in GSD and TSD dragon lizards.

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“…Clutches were incubated in an artificial in-cubation building (7 3 4 m) at a temperature and relative humidity of 30-33 C and 88-92%, respectively. This intermediate incubation temperature will normally result in a 1 : 1 male : female sex ratio (Ferguson and Joanen, 1982).…”

Section: Sites and Animal Collectionsmentioning

confidence: 99%

Necropsy Findings in American Alligator Late-Stage Embryos and Hatchlings From Northcentral Florida Lakes Contaminated With Organochlorine Pesticides

Sepúlveda

Piero

Wiebe³

et al. 2006

Journal of Wildlife Diseases

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ABSTRACT:Increased American alligator (Alligator mississippiensis) embryo and neonatal mortality has been reported from several northcentral Florida lakes contaminated with old-use organochlorine pesticides (OCPs). However, a clear relationship among these contaminants and egg viability has not been established, suggesting the involvement of additional factors in these mortalities. Thus, the main objective of this study was to determine the ultimate cause of mortality of American alligator late-stage embryos and hatchlings through the conduction of detailed pathological examinations, and to evaluate better the role of OCPs in these mortalities. Between 2000 and 2001, 236 dead alligators were necropsied at or near hatching (after ,65 days of artificial incubation and up to 1 mo of age posthatch). Dead animals were collected from 18 clutches ranging in viability from 0% to 95%. Total OCP concentrations in yolk ranged from ,100 to 52,000 mg/kg, wet weight. The most common gross findings were generalized edema (34%) and organ hyperemia (29%), followed by severe emaciation (14%) and gross deformities (3%). Histopathologic examination revealed lesions in 35% of the animals, with over half of the cases being pneumonia, pulmonary edema, and atelectasis. Within and across clutches, dead embryos and hatchlings compared with their live cohorts were significantly smaller and lighter. Although alterations in growth and development were not related to yolk OCPs, there was an increase in prevalence of histologic lesions in clutches with high OCPs. Overall, these results indicate that general growth retardation and respiratory abnormalities were a major contributing factor in observed mortalities and that contaminants may increase the susceptibility of animals to developing certain pathologic conditions.

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Temperature of egg incubation determines sex in Alligator mississippiensis

Cited by 351 publications

References 11 publications

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

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

Extension, single-locus conversion and physical mapping of sex chromosome sequences identify the Z microchromosome and pseudo-autosomal region in a dragon lizard, Pogona vitticeps

Necropsy Findings in American Alligator Late-Stage Embryos and Hatchlings From Northcentral Florida Lakes Contaminated With Organochlorine Pesticides

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