Plant & Animal Genomes XI Conference Plant & Animal Genomes XI ConferenceJanuary 11-15, 2003
Town & Country Convention Center
San Diego, CA
Workshop: Aquaculture
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Salinity tolerance is one of the commercially important traits for the fresh water fish in order to expand the farming capability into the sea. Mapping of genes responsible for the salinity tolerance of tilapia has been performed. To determine genomic regions affecting salt tolerance, we developed a pure O. niliticus F2 full sib family. A total of 398 F2 were produced, of which 298 F2 were used for mapping the salinity QTLs. These experiments were carried out in the GIFT station in the Philippines by increasing salinity of 4ppt per hour. The mortality started from 27ppt and the maximum salinity challenged was 40 ppt. All fish were genotyped with microsatellite and SNP markers at every 20 cM across the whole genome. Quantitative trait loci were detected and characterized by a multiple regression analysis. We detected two QTL regions with LOD score of 5.2 and 18.7 respectively in two different chromosomes. To confirm the effects of QTL, first, the associated markers will be tested out against a brood stock specially designed for farming in salt water and, if necessary, more detailed mapping will be done with a F3 family derived from the F2 family used for the current study, together with an effort mapping genes differentially expressed between salt and fresh water environments.