延边黄牛MYH3和MYH8基因多态性及其与生长性状的关联分析

本研究旨在探索延边黄牛肌球蛋白重链3（MYH3）和肌球蛋白重链8（MYH8）基因多态性及其与生长性状的关联性，应用DNA直接测序法和高分辨率熔解曲线分型技术对120头24月龄延边黄牛MYH3、MYH8基因的遗传变异进行分析，并结合延边黄牛生长性状数据进行了关联分析。结果显示，在MYH3基因的29602748位点检测到一处T>G突变，包含2个等位基因：T和G，存在3种基因型：TG、TT和GG；在MYH8基因的29406042位点检测到一处C>T突变，包含2个等位基因：C和T，存在3种基因型：CT、CC和TT。关联分析显示，MYH3基因29602748位点T>G突变显著影响24月龄延边黄牛十字部高和腰角宽，表现为GG基因型十字部高显著高于TT基因型（P<0.05），腰角宽显著高于TT和TG基因型（P<0.05）。MYH8基因29406042位点C>T突变显著影响24月龄延边黄牛体重和胸围，表现为CT和TT基因型体重显著高于CC基因型（P<0.05）；TT基因型胸围显著高于CC基因型（P<0.05）。本研究结果表明，MYH3、MYH8基因多态性与延边黄牛的部分生长性状相关，可作为现代肉牛育种中分子标记辅助选择的候选基因。

Analysis of MYH3 and MYH8 Genes Polymorphisms and Their Correlation with Growth Traits in Yanbian Yellow Cattle

The purpose of this study was to investigate the association of the polymorphisms of myosin heavy chain 3 (MYH3) and myosin heavy chain 8 (MYH8) gene with growth traits in Yanbian Yellow cattle.In this study,the genetic variation of MYH3 and MYH8 genes were analyzed by DNA direct sequencing method and high resolution melting curve in 120 heads of Yanbian Yellow cattle,and the correlation analysis was conducted based on the growth character data of Yanbian Yellow cattle.The results showed that a T>G mutation at locus 29602748 of the MYH3 gene was detected,containing two alleles:T and G,and three genotypes:TG,TT and GG.One C>T mutation at locus 29406042 of MYH8 gene was detected,in which there were two alleles:C and T,and three genotypes:CT,CC and TT.Correlation analysis showed that the T>G mutation at locus 29602748 of MYH3 gene significantly affected the height at hip cross and hip width of Yanbian Yellow cattle at 24 months age,that the height at hip cross of GG genotype was significantly higher than TT genotype (P<0.05),and the hip width was significantly higher than TT and TG genotypes (P<0.05).The C>T mutation at locus 29406042 of MYH8 gene significantly affected the chest circumference and body weight of Yanbian Yellow cattle at 24 months age,indicating that the body weight of CT and TT genotypes were significantly higher than CC genotype (P<0.05).Moreover,The chest circumference of TT genotype was significantly higher than CC genotype (P<0.05).In summary,the results of this study indicated that the polymorphisms of MYH3 and MYH8 genes were related to some growth traits of Yanbian Yellow cattle and could be used as candidate genes for marker-assisted selection in modern beef cattle breeding.