大口黑鲈NPY基因多态性及与生长的关联分析

Polymorphism of NPY Gene and Its Association with Growth Traits in Largemouth Bass

神经肽Y （NPY）是鱼类摄食调控网络中具有促进食欲的摄食因子,NPY基因上的多态性可能影响鱼类的摄食进而对生长性状产生影响。本研究通过PCR扩增和直接测序在大口黑鲈NPY基因5＇非编码区筛选获得1个SNP位点S1 （A-85C）。随机选取同塘饲养的12月龄大口黑鲈327尾作为分型群体,采用SNaPshot方法检测每尾鱼中S1位点的基因型,运用Popgene 32软件进行群体遗传结构分析。结果表明,S1位点共有3种基因型：AA、AC和CC,其分布频率分别为0.560、0.416和0.024。该位点在群体中的有效等位基因数（Ne）、观测杂合度（Ho）和期望杂合度（He）分别为1.928、0.450和0.449,处于哈温平衡。采用一般线性模型分析不同基因型与大口黑鲈生长性状之间的相关性,结果显示：AC基因型群体的平均体质量、体宽、全长和体高分别高于AA基因型群体和CC基因型群体,其中AC基因型个体的平均体质量比CC基因型个体的平均体质量增加了15.37%,但在统计上均没有达到显著相关（p〉0.05）。这可能与CC基因型个体明显偏少,只占分型群体的2.4%有关。

Neuropeptide Y （NPY） is a key factor in the regulation network of fish feeding and promotes appetite. The single nucleotide polymorphism （SNP） in NPY gene may affect fish feeding and it would affect growth traits. In this study, the 5＇ non-encoding region ofNPY gene in largemouth bass was amplified by PCR and a SNP （SI： A-85C） was detected by direct sequencing. 327 twelve-month-old largemouth bass that hatched at the same time and farmed in the same pond were chosen randomly for genotype analysis of S 1 site with the method of SNaPshot. Genetic structure was analyzed by software Popgene 32. These results showed that S1 site had three genotypes （AA, AC and CC）. The frequency of AA, AC and CC genotype was 0.560, 0.416 and 0.024, respectively. The effective number （Ne）, observed heterozygosity （tto） and expected heterozygosity （He） was 1.928, 0.450 and 0.449, respectively. This site was in Hardy-Weinberg equilibrium. A general linear model was used for correlationanalysis between different genotypes and growth traits. The results showed that the average values of body weight, body width, total length and body depth of the AC genotype group were higher than those of the AA genotype group and the CC genotype group, respectively. Among them, individuals with the AC genotype had 15.37% greater values for body weight than those with the CC genotypes, but the difference was no statistically significant （p〉0.05）. It might be associated with fewer individuals with CC genotype that accounted for only 2.4% in the total population.