中国荷斯坦牛PPAR-α基因多态性研究及其与耐热性能的关联分析

Study on the Polymorphisms of PPAR-α Gene and its Association with Heat Shock Response in Chinese Holstein

本研究采用PCR方法扩增牛过氧化物酶增殖物激活受体(peroxisome proliferator-activated receptors,PPAR-α)基因的内含子3,获得589 bp的片段,利用DNA测序技术发现1个新SNP位点,即44087(G/A);同时利用PCR-RFLP技术对这该SNP位点进行基因型分型,分别分析了771头中国荷斯坦牛、136头鲁西黄牛和37头渤海黑牛PPAR-α基因该位点的多态性。结果表明,在这3个群体中PPAR-α基因44087(G/A)位点普遍表现为GG基因型频率最高,优势等位基因为G;χ2适合性检验结果表明,该位点在中国荷斯坦牛和鲁西黄牛群体中都未达到Hardy-Weinberg平衡状态(P<0.05),在这个基因座位上均有丰富的多态信息含量。对中国荷斯坦奶牛44087(G/A)位点不同基因型与SCS、产奶性能及耐热性能进行最小二乘均值显著性检验结果表明,在PPAR-α基因该位点GA基因型是优良基因型,其个体的SCS值显著低于GG基因型(P<0.05),并且GA基因型乳蛋白率显著高于GG基因型(P<0.05),在炎热环境中产奶下降率显著低于GG基因型(P<0.05)。由此分析GA基因型可能有利于提高中国荷斯坦奶牛的产奶性能。在人工选择的过程中,选择GA基因型的个体,可以降低热应激给奶牛带来的危害,同时又能够提高牛奶品质和产量。

In this study,we detected a novel single-nucleotide polymorphism of the PPAR-α gene in Chinese native cattle by screening for genetic variation of PPAR-α in 944 individuals of three Chinese cattle breeds,namely China Holstein,Bohai Black and Luxi Yellow,using PCR-RFLP and DNA sequencing techniques.The sequencing results indicated that there was one single nucleotide mutation（G to A） in the 44087 of the PPAR-α gene.Chi-square test indicated that 44087GT polymorphic site in the PPAR-α gene didn＇t meet Hardy-Weinberg equilibrium in Holstein and Luxi cattle（P0.05）;The genetic correlations between genotypes and heat shock response were obtained by the least square analysis,and the results showed that genetic polymorphisms significantly correlated with somatic cell scores（SCS）,and milk productive traits.GA genotype in 44087GA polymorphic site in PPAR-α gene was an excellent site,SCS of the individuals were significantly lower than GG genotype（P0.05）;cows with GA genotype had a significantly higher protein levels and milk yield in the hot environment than GG genotype（P0.05）,so GA genotype was resistive heat.The resulting analysis of the GA genotype might help to improve the performance of Chinese Holstein cows milk.In the process of artificial selection,the GA genotype individuals could reduce heat stress to cows harm,and at the same time was able to improve milk quality and yield.