中国荷斯坦牛催乳素基因A8398G多态性与产奶性状相关性分析

采用PCR-RFLP技术对中国荷斯坦牛PRL基因第4外显子A8398G位点进行单核苷酸多态性分析。结果表明PRL基因经RsaⅠ酶切后产生2种等位基因和3种基因型。等位基因A和G的频率分别为0.257和0.743。基因型AA、AG和GG的频率分别为0.010,0.497及0.493。测序分析表明AA型和GG型相比在PRL基因第8398位碱基处发生A→G突变,该突变未导致氨基酸的改变。χ2适合性检验表明,PRL基因的RsaⅠ酶切位点处于Hardy-Weinberg不平衡状态(P<0.05)。在第Ⅱ泌乳期,最小二乘分析表明:基因型GG所对应的乳蛋白率最小二乘均值显著高于基因型AG所对应的最小二乘均值(P<0.05);基因型AG所对应的产奶量最小二乘均值显著高于基因型GG所对应的最小二乘均值(P<0.01);基因型GG所对应的线性评分最小二乘均值显著高于基因型AG所对应的最小二乘均值(P<0.05)。

Genetic polymorphisms of the prolactin gene A8398G and its correlation with milk production traits in Chinese Holstein cows

Single nucleotide polymorphisms of exon 4 A8398G of the PRL gene were detected in Chinese Holstein cows by PCR-RFLP. The results showed that the PRL gene digested by RsaⅠ could be divided into two kinds of alleles and three kinds of genotypes. The frequencies of allele A and G are 0.257 and 0.743 respectively.The frequencies of genotype AA, AG and GG are 0.010, 0.497 and 0.493 respectively. Sequencing revealed one single nucleotide mutatioo A→G at 8398 bp of the gene in genotype AA in comparison with genotype GG, and this mutation can not result in an amino acid change. The result of Chi Square test indicated that the frequencies of patterns types of PRL gene genes digested by RsaⅠ can not fit with the Hardy-Weinberg equilibrium in this population(P<0.05). In lactation Ⅱ, the least squares means of protein percentage of this population was higher for genotype GG than for genotype AG (P<0.05). The least squares means of milk yield of this population was higher for genotype AG than for genotype GG (P<0.01). The least squares means of linear score of this population was higher for genotype GG than for genotype AG (P<0.05).