斑点叉尾GHRH基因3个SNPs位点及其单倍型组合与生长性状的关联分析

研究旨在探讨生长激素释放激素基因（Growth hormone-releasing hormone，GHRH）对斑点叉尾鲖（Ictalurus punctatus）生长性状的影响。采用DNA混池测序法筛选GHRH基因的单核苷酸多态性（Singlenucleotide polymorphisms，SNPs）位点，使用SNaPshot法将筛选到的SNPs多态性位点进行分型，并对这些位点进行连锁不平衡和单倍型分析。结果表明，在GHRH基因内含子区域共检测到4个SNPs位点，并成功地对3个位点进行了分型，3个位点间均不存在强连锁不平衡；3个SNPs位点在176尾斑点叉尾鲖中形成了6种有效单倍型。关联分析表明SNP位点g.6301 GA的AA基因型的体质量显著性地高于AG和GG型（P0.05），比群体的平均体质量高14%。单倍型组合H1/H4和H1/H5个体的体质量和体长极显著性地高于其他单倍型组合（P0.01），体质量比群体平均体质量分别高30%和15%，体长比群体平均体长分别高7%和6%。研究为斑点叉尾鲖生长性状分子标记辅助选育和QTL定位提供了参考依据。

THREE SNPS POLYMORPHISM OF GROWTH HORMONE-RELEASING HORMONE GENE (GHRH) AND ASSOCIATION ANALYSIS WITH GROWTH TRAITS IN CHANNEL CATFISH

This study assessed the effects of growth hormone-releasing hormone (GHRH) gene on channel catfish (Ictalurus punctatus) growth traits by identifying SNPs of GHRH gene by The Pooled DNA sequencing using 176 individuals from core breeding population of channel catfish by multiplex SNaPshot genotyping method and analyzing the associations between growth traits with genotypes and diplotypes of GHRH SNPs. Four SNPs (g.4333 AG, g.4616 AC, g.4632AT and g.6301 GA) were identified in intron, and three of them were genotyped successfully, and there were no strong LD between the SNPs. Six haplotypes and six diplotypes were found in these 176 channel catfish. Association analysis between these SNPs and growth traits showed that the individual with genotype AA of the mutation g.6301 GA had significantly higher body mass and body length than those with genotype GG and AG (P0.05); H1/H4 and H1/H5 of six diplotypes had the highest body mass and body length, which were significantly (P0.01) higher than those of the other diplotypes. This study provide basic knowledge for marker-assisted breeding and QTL of growth traits of channel catfish.