中国荷斯坦奶牛GPR120基因SNP位点鉴定及其与产奶性能的关联分析

Association analysis between SNP locus of GPR120 gene and milk production traits in Chinese Holstein cows

为研究GPR120基因单核苷酸多态性及其与中国荷斯坦奶牛产奶性能的相关性,选取518头中国荷斯坦奶牛为试验对象,提取其总DNA后,PCR扩增GPR120的3个外显子基因片段,筛选目的片段SNP(singlenucleotide polymorphism)位点,进而利用在线软件(RNAfoldwebserver及SOPMA)对突变前后GPR120mRNA和蛋白质的二级结构进行功能分析,最后统计学分析遗传多态性位点与奶牛产奶性能的相关性。结果显示,在中国荷斯坦奶牛的目标群体中,在GPR120基因第一外显子中共鉴定获得9个SNP位点,其中T^(100)G、G^(413)A、C^(428)T、C^(904)T4个位点为错义突变。通过关联分析发现其中的G^(413)A位点与305d日产奶量及乳脂率显著相关(P<0.05),与乳蛋白率及体细胞评分呈极显著相关(P<0.01)。T^(873)G位点与305d日产奶量、乳脂率和乳蛋白率具有极显著相关(P<0.01)。表明GPR120第一外显子处的2个SNP位点G^(413)A和T^(873)G与奶牛产奶性状密切相关,在一定程度上影响牛奶产量、乳脂、乳蛋白含量,其可作为影响奶牛泌乳性能的候选分子辅助选择标记,同时该结果为后续GPR120基因在中国荷斯坦奶牛乳脂合成中的调节机制研究奠定基础。

To study the correlation between the single nucleotide polymorphism(SNP)of GPR120 gene and the milk performance of Chinese Holstein cows.Five hundred and eighteen Chinese Holstein cows were selected as test subjects,and their total DNA was extracted.the three exons of GPR120 were amplified by PCR and the SNP sites of the target fragment were screened,then the functional analysis of the secondary structure of GPR120 mRNA and protein before and after the mutation was performed using online software(RNA fold web server and SOPMA).Then,the correlation between genetic polymorphism and milk quality traits was statistically analyzed.The results showed that nine SNP loci were found in the first exon of GPR120 gene in Holstein dairy cows,among which four loci,T^(100)G、G^(413)A、C^(428)T,and C^(904)T4T were missense mutations.The results of correlation analysis showed that the G;A site was significantly correlated with 305-day milk production and milk fat rate(P<0.05),and was extremely significantly correlated with milk protein rate and somatic cell score(P<0.01).The T;G locus has extremely significant correlation with the daily milk production,milk fat rate and milk protein rate on d 305(P<0.01),suggesting that the two SNP sites G^(413)A and T^(873)G in the first exon of GPR120 are closely related to milk production traits,and affect milk production,milk fat,and milk protein content to a certain extent and can be used as candidate molecular assistants to affect the lactation performance of dairy cows.These results lay the foundation for subsequent research on the role of GPR120 gene in milk fat synthesis in Chinese Holstein cows.