Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Workshop: Aquaculture
            

COMPARATIVE MAPPING OF SEX DETERMINING GENES IN TILAPIA

Hubbard Center for Genome Studies, University of New Hampshire, Durham NH,03824, USA

Tilapia (Oreochromis spp.) are a popular fish in aquaculture industry. Male tilapia grow faster than females and mono-sex culture of male tilapia improves the economics of production. Sex determination has been suggested to be controlled by an XY system in O. niloticus and O. mossambicus and by a WZ (female heterogametic) system in O. aureus. We took advantage of the linkage map from the intercross F₂ between O.aureus X O. niloticus to identify genes for sex determination. We identified a QTL for sex near three microsatellite markers (GM271, GM204, and GM354) using the nonparametric procedure in MapQTL4.0. To identify candidate genes in the region, we isolated BAC clones containing these markers. Partial shotgun sequences were determined for three clones and compared to the public databases using BLAST. Several hits to known or predicted genes were obtained, and form the basis for preliminary comparative maps. We will also report on sex-linkages in two other crosses which are currently being genotyped.