Isolating sex-specific DNA in dragons to test models of sex determination

Sex in vertebrates is usually determined genotypically (GSD), but in many reptiles sex is determined by incubation temperature (TSD). Currently, the evolutionary relationship between TSD and GSD is obscure. Sex-specific DNA in TSD species would indicate that both modes of sex determination can occur within the same individual and would conflict with current dogma. To test this proposition, we will use Representational Difference Analysis to isolate sex-specific DNA in a GSD dragon lizard, and then test for that DNA in a closely related TSD species. This will provide a model system for a comprehensive analysis of the evolution of sex determination.