麦洼牦牛GH、GHR、GHSR基因的SNPs检测及其与体尺性状的关联分析

Identification of SNPs in GH,GHR and GHSR Genes and Their Association with Body Measurement Traits in Maiwa Yak

旨在探讨生长激素(Growth hormone,GH)、生长激素受体(Growth hormone receptor,GHR)、生长激素促分泌素受体(Growth hormone secretagogue receptor,GHSR)基因在麦洼牦牛中的遗传多样性,揭示不同基因型与其生长性状的关联性,同时为候选基因在牦牛中的表达调控提供理论依据,寻找可用于遗传育种辅助选择的分子标记。本试验采用DNA池技术,结合PCR-RFLP和直接测序法研究麦洼牦牛GH、GHR、GHSR基因的遗传多态性,分析候选基因多态位点与体高、体斜长、胸围、管围和体重等生长性状的关联性。结果表明:1)麦洼牦牛GH、GHR、GHSR基因均存在多态性,其中GH基因存在A757G和T949C2个SNPs位点,GHR基因发现T2416C、T3490C和A7500G3个突变位点;GHSR基因存在T1387C和T3006C突变;2)适合性检验表明,GHR基因A7500G位点在粉嘴类群,及GHSR基因T3006C位点在纯黑类群中偏离Hardy-Weinberg平衡状态,其他位点均符合Hardy-Weinberg平衡;3)差异显著性检验表明,GHR基因T2416C、T3490C和A7500G位点与麦洼牦牛管围极显著相关(P<0.01),GHSR基因T1387C位点与其体重显著相关(P<0.05)。麦洼牦牛GH、GHR、GHSR基因均存在遗传多态性,推断GHR基因T2416C、T3490C和A7500G位点、GHSR基因T1387C位点可能是影响麦洼牦牛管围、体重性状的主基因或与主基因相连锁的基因座,可作为辅助选择的遗传标记。

The aims of this study were to determine the genetic diversity of the GH,GHR and GHSRgenes in Maiwa yak,to reveal the association between different genotypes and growth traits,to provide the theoretical foundation for the expression regulation of the candidate gene in yak and to look for the molecular marker that can be used for the assistant selection for genetic breeding.The DNA pool technology,PCR-RFLP and the direct sequencing were adopted to study the genetic polymorphism of the GH,GHRand GHSRgenes in Maiwa yak and to analyzethe association between the polymorphism of the candidate genes and the growth traits,such as withers height,body length,chest circumference,cannon circumference and body weight.The results showed that：1）The GH,GHRand GHSRgenes of the Maiwa yak were all with the polymorphism,among which the GH gene had 2SNP sites（A757Gand T949C）.Three mutation sites are found on the GHR gene（T2416C,T3490 Cand A7500G）.T1387 Cand T3006C mutations existed on the GHSRgene.2）The fitness test indicated that the A7500 Gof the GHRgene in the pink lip group and the T3006 Cof the GHSRgene in the pure black group all deviated from the Hardy-Weinberg equilibrium while the other sites all conformed to the Hardy-Weinberg equilibrium.3）The different significance test indicated that the T2416 C,T3490Cand A7500 Gof the GHRgene were significantly related to the cannon circumference of the Maiwa yak（P〈0.01）,while the T1387 Cof the GHSRgene was significantly related to body weight（P〈0.05）.The results indicate that the GH,GHRand GHSRgenes of the Maiwa yak are all with the genetic polymorphism,and it is deduced that the T2416 C,T3490Cand A7500 Gof the GHRgene as well as the T1387 Cof the GHSRgene may be the major effect genes influencing the cannon circumference and body weight of the Maiwa yak or the loci may be closely linked to the major effect genes and they can be regarded as the genetic markers for the assistant selection.