Friday 6 May 2011 | 12.30pm - 2.00pm | Nathan campus: N13_0.32
Dr. Craig Smith
Group Leader, Comparative Development,
Murdoch Childrens Research Institute and University of Melbourne Department of Paediatrics
Royal Children’s Hospital, Melbourne, Australia
Biography
Craig Smith is a developmental biologist based in Melbourne, Australia. His research interests focus on sex determination and gonadal development in vertebrate embryos. Craig graduated in 1995 with first class Honours and a PhD in Zoology at Macquarie University in Sydney. Working with Professor Jean Joss, he studied the mechanism of temperature-dependent sex determination in crocodilian embryos (crocodiles and alligators). He then joined the University of Melbourne Department of Paediatrics as a postdoctoral fellow, working with Andrew Sinclair to pioneer the use of the chicken embryo as a model for vertebrate gonadal development. His research has defined the molecular and cellular processes underlying testis versus ovary development in the avian (chicken) model. Most recently, he has developed the use of virally delivered RNAi to manipulate gene expression in living chicken embryos. Craig currently heads the Comparative Development Group at the Murdoch Institute in Melbourne.
Presentation Title
A bird's eye view of sex; the chicken embryo as a model for sex determination and gonadal development.
Abstract
The development of sexual phenotype must have a long evolutionary history in animals. However, despite its antiquity, sex is determined by different triggers in different animals. For example, in vertebrates, sex can be determined by genetic or environmental cues. In birds, sex is set in the early embryo by the inheritance of sex chromosomes (ZZ male and ZW female). We use the chicken embryo as a model for understanding the genetics and cell biology of sex determination and how it has evolved. Genes carried on one or both of the sex chromosomes must control gonadal sexual differentiation during embryonic life, producing testes in males (ZZ) and ovaries in females (ZW). This presentation will summarise our current understanding of avian gonadal development, with emphasis on the evolution of sex determination. This process involves the sex-linked DMRT1 gene. If DMRT1 gene activity is experimentally reduced, the gonads of male embryos (ZZ) are feminised, with ovarian type structure, down-regulation of male markers and activation of female markers. DMRT1 is currently the best candidate gene thought to regulate testicular differentiation. Female development in the avian model appears to be similar to that of mammals; both the FOXL2 and RSPO1/WNT4 pathways are implicated in ovarian differentiation.