DNA polymorphism in the growth hormone gene and its association with weight in olive flounder Paralichthys olivaceus

ABSTRACT: Variation within the growth hormone gene and its association with growth trait in the olive flounder ( Paralichthys olivaceus ) was investigated. Based on Southern blot analysis and using various kinds of restriction endonucleases, it was demonstrated that the growth hormone gene exists as a single copy gene in the olive flounder. Polymorphisms of various lengths were also detected by Southern blot analysis, and by the subsequent digestion of the polymerase chain reaction (PCR) -amplified growth hormone gene fragment with Sau 3AI restriction enzyme. To study the possible association between variation in the growth hormone and weight, 60 progenies of the hatchery strain of three various sizes (large, medium and small weight) were selected and the entire genetic structure of the growth hormone gene was analysed. A total of 15 different genotypes was observed from the random association of six haplotypes. Significant heterogeneity of the growth hormone gene with haplotype and genotype frequencies was detected among the different-sized groups.