牛生长激素受体基因多态性与体尺、体重指标的相关性分析

利用PCR-SSCP技术对南阳牛、利木赞、盖洛威共100头牛的生长激素受体基因的外显子10(GHR10)部分序列进行单核苷酸多态性研究, 并分析了该基因的不同基因型与3个品种牛生产性状的关系。结果表明: 南阳牛、利木赞、盖洛威3个品种中共存在6种基因型(AA、BB、CC、AB、AC、BC), c2检验表明该实验群体在这一位点上处于Hardy-Weinberg平衡状态(P > 0.05), 利木赞和盖洛威的PIC表现为中度多态,而南阳牛表现高度多态。测序结果显示: 所扩增GHR10部分片段共有5处碱基突变, 分别是495 bp (A/T), 622 bp(C/T), 650 bp(A/C), 702 bp(T/C), 730 bp(A/G); 并导致3处氨基酸替代: 其中622 bp Pro/Ser(脯氨酸/丝氨酸), 650 bp Asn/Thr(天冬酰胺/苏氨酸), 730 bp Ser/Gly(丝氨酸/甘氨酸)。最小二乘分析表明: 基因型AB、BC所对应的12月龄体重最小二乘均值显著高于基因型CC所对应的最小二乘均值(P < 0.05, P < 0.01); 18月龄体重BC基因型显著高于CC基因型(P < 0.01), 基因型AB所对应的18月龄胸围最小二乘均值显著高于基因型CC所对应的最小二乘均值(P < 0.05)。

Analysis of the correlations between growth hormone receptor gene polymorphism and body size indexes in cattle

Polymorphism in exon 10 of growth hormone receptor (GHR) was detected in three cattle breeds (Nanyang cattle, limousin and galloway), They were at A/T at nt. 495, C/T at nt. 622, A/C at nt. 650, T/C at nt. 702 and A/G at nt. 730. Results indicated that there were six genotypes, namely AA, BB, CC, AB, AC and BC. The frequencies of different genotypes in different breeds and the relationship between the six genotypes and traits of these cattle were analyzed using a linear model. Statistical results showed that the GHR SSCP sites in Nanyang, Limousin and Galloway cattle were at Hardy-Weinberg Equilibrium. The polymorphism information content (PIC) values indicated that the SSCPs were highly polymorphic (PIC < 0.50) in the Nanyang breed, and were moderately polymorphic in Limousin and Galloway breeds. The least squares means of body weight of 12-month-old cattle was lower for genotype CC than for genotypes AB and BC (P<0.05, P<0.01, respectively). The least squares means of body weight of 18-month-old cattle was lower for genotype CC than for BC (P < 0.05). The least squares means of heart girth in 18-month-old cattle was lower for genotype CC than for AB (P < 0.05). There was no difference in the genotype distribution among other genotypes.