草鱼MSTN-1基因多态性及与早期生长性状和肌肉成分关联分析

Polymorphism of MSTN-1 and the association with growth traits and muscle compositions of juvenile grass carp(Ctenopharyngodon idella)

为研究草鱼MSTN-1基因多态性及与早期生长性状和肌肉成分的相关性,本研究扩增出全长为3824 bp的草鱼MSTN-1基因,用长江选育草鱼群体对MSTN-1基因多态性进行筛选和验证。结果共发现3个多态性位点(Locus 1:C1799T,野生型EE/突变型EF;Locus2:C1842T,野生型HH/突变型HI;Locus 3:TGAAGCGCTGGTTCT/2585-,野生型BB/缺失型BD)。利用一般线性模型分析3个位点及其组合型(剔除个体数少于3的组合)与生长性状和肌肉成分的相关性,发现2个位点对幼鱼生长性状表型差异有显著影响,但3个位点对肌肉成分差异均无显著影响。多重比较发现,单倍型HI突变组的体长和体质量显著高于HH野生组,BD突变组的体长和体质量显著性低于BB野生组;多倍型中存在HI突变组合的体长、体质量均显著高于其他组,存在BD突变的组合在体长性状方面显著低于其他组。表明草鱼MSTN-1基因3个SNPs中,HI突变是对草鱼生长性状的有利突变,BD突变是不利突变,而EF突变无显著影响,可将MSTN-1基因作为分子标记辅助草鱼选育的候选基因。

Previous studies suggested that the myostatin-1 （MSTN-1） gene played as an important role in the growth and development of grass carp （Ctenopharyngodon idella）. In order to determine whether the polymorphism of grass carp MSTN-1 gene was associated with growth traits and muscle compositions, 192 individuals from Yangtze River were used in this study. Three polymorphic loci were found in the 3824 bp MSTN-1 gene： C1799T, C1842T and TGAAGCGCTGGTTCT/2585-, which were named Locus 1 （wild-type EE/mutant EF）, Locus 2 （wild-type HH/mutant HI） and Locus 3 （wild-type BB/deletion type BD）, respectively. A general linear model was used to analyse the correlation between those three single nucleotide polymorphisms （SNPs） and grass carp traits. The results showed that two SNPs have a significant influence on grass carp growth traits. Whereas, none of those SNPs have a significant effect on grass carp muscle compositions. Multiple comparisons found that the body length and body weight of individuals with HI genotype were significantly higher than that of wide-type individuals, conversely, mutant individuals with BD genotype were significantly lower than wide-type individuals at body length and body weight in haplotype analysis; the groups with HI or BD genotype also had the similar results in fold type combinations analysis, while the body length of groups with BD genotype were not significantly lower than other groups. Results indicate that HI is a beneficial mutation on growth traits, while BD is a detrimental mutation on grass growth traits. Preliminary study indicated the MSTN-1 gene could be a candidate modifier gene in Molecular Marker-assisted Selection （MAS） of grass carp.