Plant & Animal Genome IX Conference

Workshop: Aquaculture
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USDA/ARS CATFISH GENOMICS RESEARCH

USDA/ARS Catfish Genetics Research Unit, Thad Cochran National Warmwater Aquaculture Center, P.O. Box 38, Stoneville, MS 38776, USA

The current version of the catfish genetic linkage map contains 243 type II (random) loci, 19 type I (expressed) loci, and 1 EST in 32 linkage groups covering 1956 cM. Nine more type II loci are contained in three twopoint linkage groups covering 24.5 cM. The average marker interval is 8.7 cM. Current efforts are concentrated on increasing marker density by adding type I markers. Over 3500 unique cDNA clones were sequenced from the 5' end, and microsatellite sequences were detected in approximately 10% of the clones. Library enrichment increased the frequency of microsatellites to 60%. A normalized cDNA library from developing fry is currently in production. Juvenile catfish from 110 spawns of the USDA103 line were compared for phenotypic traits. Specific growth rates from 50-110 days of age ranged from 0.86% to 2.86% per day (avg=1.68%). Mean family survival 21 days after exposure to virulent Edwardsiella ictaluri ranged from 6.7% to 100% (avg.=65.7%). Microsatellite genotype analysis was used to identify full and half-sib families within this population, and phenotypic and genetic parameters for these traits will be estimated from an animal model.