Sex in Reptiles

Abstract

I'm trying to understand the evolutionary history of chromosomes, particularly the sex chromosomes in the major reptile groups. Apart from mammals, which branched off early in evolution, every other terrestrial vertebrate alive today comes from the ancient reptilian stock including the feathered dinosaurs, better known as birds! Reptiles have a remarkable diversity in sex chromosome systems, from XY systems like that of mammals, to ZW as in birds and snakes. Some have no obvious sex chromosomes. Others still use temperature to determine the sex of their offspring and in some like the Australian bearded dragon, both temperature and chromosomes play a part. I'm using advanced cytogenetic techniques like chromosome microdissection, chromosome painting and gene mapping to determine how evolution has sorted the ancient reptilian's chromosomes amongst today's snakes, lizards, tuataras, crocodiles and birds. I'm hoping to answer some fundamental questions about how sex is determined in reptiles and about the evolution of sex chromosomes. Northern Australia is home to many species of lizards and snakes that are found nowhere else and many occupy a unique evolutionary position. I'm hoping to collect a representative sample of these species and identify how their sex chromosomes have evolved, and which genes are involved in sex determination. My research will provide a greater understanding of the myriad ways nature solves that most fundamental biological dichotomy: sex. It may also lead to a greater understanding of human disorders of health and reproduction. Abnormalities in humans are often the norm in other species and understanding their origins may lead to novel remedies. Show more