Plant & Animal Genomes XI Conference Plant & Animal Genomes XI ConferenceJanuary 11-15, 2003
Town & Country Convention Center
San Diego, CA
Workshop: Aquaculture
Channel catfish is the most economically important aquacultured species in the United States, and selective breeding programs are underway to produce improved germplasm. The channel catfish mitochondrial genome has been sequenced and is typical of vertebrates. Phylogenetic analyses of all mitochondrial proteins point to a basal relationship of catfish with the cyprinids, salmonids and more advanced lineages such as the cods and perches. While mitochondrial D-loop variation has shown limited utility for delineating catfish populations, nuclear markers such as microsatellites have proven useful in the detection of full and half-sib families for the estimation of genetic variation, and parentage detection in mixed pond cultures. Microsatellite marker genotypes have also been instrumental in the development of a new strain released to the U.S. catfish industry. The current catfish genetic linkage map contains 263 polymorphic microsatellite markers with an average intermarker distance of 8.7 cM, and more coding loci are being placed on the map to facilitate comparative mapping with other species. Three catfish BAC libraries have been produced, two from a gynogenetic female (CCBL1, CCBL2) and one from a diploid male (CHORI-212), for an approximate 17-fold genomic coverage. The CCBL1 library contains clones from each linkage group, and clones have been identified for all genes searched to date. The BAC libraries will be useful for the production of a physical map, and integration of the linkage and physical maps. Another molecular tool, quantitative real-time detection of the bacterial pathogen E. ictaluri, is being used to analyze disease resistance in select families.