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Sex in Dragons
The molecular basis of genetic and environmental sex determination
How animals determine sex has been debated over decades.
Particularly mysterious is that sex is determined by genes in some animals, and by temperature in others.
We are studying closely related dragon lizards which determine sex via genes (GSD) or temperature (TSD).
Our approach is to use novel genetic, molecular and cytological approaches to discover genes and chromosomes
that control sex determination in the GSD species, and explore their homologues in the TSD species.
We expect this study will provide new insights to mechanisms of sex determination in all vertebrates,
and demonstrate how genes and the environment interact to control the process.
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Professor Arthur Georges
We now plan to expand our models to include transitions between GSD and TSD and between XY and ZW systems of sex determination.
We also plan to identify and characterise the homologous chromosome and gene(s) in closely related reptiles, both TSD and GSD.
We hope then to discover how the sex determining pathways in the related GSD and TSD species differ and reconstruct how
transition between GSD and TSD occur in evolution.
Our work will provide new insights to the mechanisms of sex determination in vertebrates.
The potential payoffs for understanding reproductive processes
in other vertebrates have driven a huge interest in the mechanisms of sex determination.
However, research to date has not capitalised on the immense opportunities offered by the
study of the diverse range of sex determining mechanisms in reptiles, where the link between
the genotype and phenotype is more complex. Most studies have been restricted to mammals,
which are relatively conservative in their mode of sex determination.
In a context where insights are often derived from oddities and exceptions to the
rule, "studies on sex determination in non-mammalian vertebrates will undoubtedly throw
light on the human situation" (Mittwoch, 2000).