Alexander E. Quinn

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Sex in reptiles is determined by genes on sex chromosomes or by incubation temperature. Previously these two modes were thought to be distinct, yet we show that high incubation temperatures reverse genotypic males (ZZ) to phenotypic females in a lizard with ZZ and ZW sex chromosomes. Thus, the W chromosome is not necessary for female differentiation. Sex(More)
The bearded dragon, Pogona vitticeps (Agamidae: Reptilia) is an agamid lizard endemic to Australia. Like crocodilians and many turtles, temperature-dependent sex determination (TSD) is common in agamid lizards, although many species have genotypic sex determination (GSD). P. vitticeps is reported to have GSD, but no detectable sex chromosomes. Here we used(More)
An individual's sex depends upon its genes (genotypic sex determination or GSD) in birds and mammals, but reptiles are more complex: some species have GSD whereas in others, nest temperatures determine offspring sex (temperature-dependent sex determination). Previous studies suggested that montane scincid lizards (Bassiana duperreyi, Scincidae) possess both(More)
Current paradigms may substantially underestimate the complexity of reptilian sex determination. In previous work, we have shown that the sex of a hatchling lizard (Bassiana duperreyi, Scincidae) does not depend entirely on its genes (XX versus XY sex chromosomes); instead, low nest temperatures can override genotype to produce XX as well as XY males. Our(More)
Distribution of sex-determining mechanisms across Australian agamids shows no clear phylogenetic segregation, suggesting multiple transitions between temperature-dependent (TSD) and genotypic sex determination (GSD). These taxa thus present an excellent opportunity for studying the evolution of sex chromosomes, and evolutionary transitions between TSD and(More)
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(More)
Primary cell lines were established from cultures of tail and toe clips of five species of Australian dragon lizards: Tympanocryptis pinguicolla, Tympanocryptis sp., Ctenophorus fordi, Amphibolurus norrisi and Pogona vitticeps. The start of exponential cell growth ranged from 1 to 5 weeks. Cultures from all specimens had fibroblastic morphology. Cell lines(More)
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(More)
Sex in many organisms is a dichotomous phenotype--individuals are either male or female. The molecular pathways underlying sex determination are governed by the genetic contribution of parents to the zygote, the environment in which the zygote develops or interaction of the two, depending on the species. Systems in which multiple interacting influences or a(More)
Sex determination in the endemic Australian lizard Bassiana duperreyi (Scincidae) is influenced by sex chromosomes and incubation temperature, challenging the traditional dichotomy in reptilian sex determination. Analysis of those interactions requires sex chromosome markers to identify temperature-induced sex reversal. Here, we report the isolation of Y(More)
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