中文摘要：

为明确牦牛乳中κ-酪蛋白中遗传多样性,以κ-酪蛋白基因（CSN3）的IV外显子为研究对象,采用PCR-RFLP方法对麦洼牦牛的CSN3进行分析,旨在从分子水平揭示κ-酪蛋白在牦牛乳中遗传多样性分布.并以CSN3的IV外显子序列建立牛属κ-酪蛋白的系统发育树,从而分析进化关系.结果表明,牦牛乳中κ-酪蛋白多数以纯合体形式存在,并发现了一个新的变异体GU441771.牛属CSN3的系统发育树分析表明,κ-酪蛋白在进化上存在一定的物种特异性.

英文摘要：

A polymorphism of κ-casein gene CSN3 exon IV was identified in Chinese Maiwa Yak by PCR-restriction fragment length polymorphism protocol to reveal the distribution of diversity of κ-casein in Maiwa Yak at the DNA sequence level.The sequences corresponding to the coding region of κ-casein gene exon IV were used for phylogenetic analysis to establish the phylogenetic relationship of CSN3 variants in the Bos genus.Experimental results indicated that most yak milks were with κ-casein BB genotype.A new variant was identified in Maiwa yak breed by analysis and entered into GenBank with accession number GU441771.The phylogenetic analysis presented κ-casein evolution was consistent with species at a degree.