Submitted to: Colloquium on Domestic Animal Cytogenetics and Gene Mapping
Publication Type: Abstract Only
Publication Acceptance Date: July 17, 1997
Publication Date: N/A
Technical Abstract: Commercial production of channel catfish, Ictalurus punctatus, is the largest single-species aquaculture enterprise in the United States. From 1980 to 1995, production grew from 46.5 million pounds to over 445 million pounds of fish processed, and total processor sales grew from 27.7 million lbs. to 227 million lbs. Although development and commercial use of improved germplasm have dramatically increased production efficiency in many livestock species, advances in catfish genetics have not had significant commercial impact. Such production increases should be possible through genetic improvement of domestic catfish, which exhibit significant phenotypic and genetic variation and positive response to selection for economically important traits. We are characterizing microsatellite loci in channel catfish for use in a marker assisted selection program. We have cloned several hundred microsatellite loci isolated from a plasmid library containing 300-1500bp inserts of channel catfish genomic DNA. To date, 76 loci have been characterized in feral, commercial, and research populations. These populations contain from 2 to 33 alleles per locus, and half of the loci contain 8 or more alleles. Loci with 2-4 alleles usually contained one predominant allele so heterozygosity was low (avg. = 0.44). However, heterozygosity was high in loci with 5 or more alleles (avg. = 0.78). Levels of heterozygosity in research and commercial populations are similar to the feral populations. We have used microsatellite genotyping to determine parentage of anonymous spawns removed from ponds, so it is now possible to measure spawning success in individuals. The loci will also be used in a strain verification program of genetically distinct broodstock.