Significant associations between prolactin gene polymorphisms and growth traits in the channel catfish (Ictalurus punctatus Rafinesque, 1818) core breeding population

Abstract

The aim of this study was to analyze the effects of the prolactin gene (PRL) on growth traits in channel catfish (Ictalurus punctatus). We sequenced pooled DNA samples from channel catfish to identify single nucleotide polymorphisms (SNPs) in the PRL gene. The identified SNPs were then genotyped in 176 individuals from the G1 core breeding population of catfish using the multiplex SNaPshot method. SNP genotypes and diplotypes of the PRL gene and their associations with body mass and body length traits were also examined. Seven SNPs (g.951A>C, g.1293A>T, g.1359C>T, g.1374A>G, g.1620C>T, g.2675C>T, and g.3369A>G) were identified in introns and noncoding regions, and five of these were successfully genotyped. Seven haplotypes and ten diplotypes occurred in the group of 176 catfish. Association analyses showed that the g.1620 C>T SNP was significantly associated with growth traits in channel catfish, such that individuals with the TT genotype had significantly greater body weights and body lengths than those with CC or CT genotypes (P < 0.05). In addition, the g.3369 A>G SNP showed a significant negative association with growth traits, such that fish with the GG genotype had lower values for both growth traits compared with fish with genotype AA or AG (P < 0.05). Diplotypes H3/H3 and H4/H7 were associated with significantly higher body mass and body length than the other diplotypes (P < 0.01). The results of this study may provide basic data for marker-assisted selection and quantitative trait loci analysis of growth traits in channel catfish.