ARS | Publication request: Golden catfish microsatellite analysis reveals a distinct Iinbred stock of channel catfish

Submitted to: Catfish 2010: The 2nd International Catfish Symposium
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2010
Publication Date: N/A

Technical Abstract: Golden-colored fish have been reported for rainbow trout, tilapia, several species of carps and Clarias catfish. The current golden catfish stock was created through mixing fish with predominant gold/yellow pigment and spots to normal sized and colored catfish. The golden catfish possess a distinct, milder flavor, and fillet chemical analysis revealed lowered fat composition than non-golden channel catfish. We conducted a genetic survey of golden catfish to determine the genetic architecture of this population. Genomic DNA was isolated from 24 catfish with the golden phenotype (GC), 24 channel catfish at the same location with normal phenotype (CC), and 24 catfish with normal phenotype chosen randomly from a commercial population (IP). Genotypes were determined by PCR amplification of 17 microsatellite loci and alleles were resolved to determine allele frequency, locus heterozygosity, and population structure (assignment based on allele frequency). Genotypic analyses revealed an average of 9.8 alleles per locus over all populations. The CC and IP populations contained 12.6 alleles per locus whereas the GC population contained only 4.2 alleles per locus. Population assignment analysis segregated the GC population from the CC and IP populations, and the CC and IP populations did not differ from each other. However, the observed average heterozygosity was high for all three populations (GC = 0.757, CC = 0.852, IP = 0.863). These data suggest a genetic bottleneck in the GC population that likely arose through selection of few individuals that displayed the phenotype, but maintenance of heterozygosity through random mating within the GC population.