Ancient bird-like sex chromosome

The astounding variety of animal sex chromosomes suggests that they have evolved independently many times. However, the recent discovery that a bird, a gecko lizard, and the platypus, share a genetically homologous sex chromosome suggests the converse, that an ancient sex chromosome system has been retained in these distantly-related lineages. We propose to test these competing hypotheses by using the diverse sex chromosomes of Australian reptiles to examine sex chromosome homology across species and identify new candidate sex determining genes. This project will reveal how sex chromosomes have evolved in reptiles and will help understand the very great diversity in sex determining modes in reptiles, and in vertebrates more generally.