Investigating the origin of mammal sex chromosomes
Undertake a research project that investigates the origin of therian sex chromosomes.
Genes from the therian X map predominantly on platypus autosome 6, including the therian gametolog of Sry, Sox3. This showed that the therian sex chromosomes evolved after the divergence of monotremes.
Alternatively the ancestral mammalian sex chromosomes may have been replaced by a different sex chromosome system in the monotreme lineage. In order to investigate these different possibilities we investigated if platypus chromosome 6 shows any signatures of sex chromosome differentiation that may have been maintained in monotremes.
Surprisingly we discovered sex specific changes in Sox3 and show that platypus chromosome 6 homologs segregate non randomly into sperm.
Our current work investigates the meiotic pairing and association of chromosome 6 with nucleolus and sex chromosomes at male meiosis, which might provide insights into the mechanisms of this unusual organisation of platypus chromosome 6.
The extent of this differentiation and whether this may predate monotreme divergence is as yet unclear.
Study genetics, monotreme genomics, evolution and conservation
Our research interest is to understand how genes and genomes have evolved different function and organisation.
We are using species that occupy key evolutionary positions such as monotremes (platypus and echidna) and birds (predominately chicken).
Areas we work in include sex determination, sex chromosome organisation and the evolution of monoallelic gene expression.
We also collaborate with industry partners to develop genetic and genomic application in conservation biology and human disease.