W632 Sex determination in poeciliids, a focus on the platyfish xiphophorus maculatus

Date: Sunday, January 15, 2012
Time: 4:10 PM
Room: Royal Palm Salon 5-6
Delphine Galiana , ENS de Lyon, IGFL, Lyon, France
Astrid Böhne , ENS de Lyon, IGFL, Lyon, France
Marta Tomaszkiewicz , ENS de Lyon, IGFL, Lyon, France
Manfred Schartl , University of Wuerzburg, Bavaria, Germany
Jean-Nicolas Volff , ENS de Lyon, IGFL, Lyon, France
Sex determination in fish is under the control of diverse mechanisms (environmental/genetic sex determination systems) and different sex determination systems can be found in a same genus or species. The only known sex-determining gene in fish is dmrt1bY in the medaka, but this gene is not the universal one in fish. To better understand the molecular mechanisms of sex determination/chromosomes evolution, it is necessary to identify other key components of the sex determination/differentiation cascade. The Xiphophorus maculatus, our laboratory model, with male or female heterogamety is useful to study the diversity of genetic sex determination in poeciliids, and in fish. Bioinformatic and molecular analyses of 50 BACs covering the sex-determining region of the X and Y chromosomes of the platyfish are performed in order to identify gene candidates for the sex determination/differentiation cascade. First, gene prediction is performed and then putative genes are annotated and their functions described compared with available data. Genes with a function related to sexual development and pigmentation are of the greatest interest. Molecular phylogenetic analyses are also performed in order to retrace the evolutionary history and distribution of gene candidates within vertebrates. Next, molecular analyses are done in order to better characterize the candidate genes. Finally, functional analyses (in well-established fish models like zebrafish or medaka) are necessary to assess the function of the genes and try to identify the master sex-determining gene in the platyfish.