贵州荷斯坦奶牛甘油二酯酰基转移酶基因多态性及其与产奶性状的关联分析

Analysis of the Polymorphisms of DGAT1 Gene and its Association with Milk Production Traits in Guizhou Holstein Cows

甘油二酯酰基转移酶(diacylglycerol acyl-transferase 1,DGAT1)是控制甘油三脂合成的关键酶。近年来DGAT1基因被鉴定出来,被认为是奶牛乳脂率的一个重要功能候选基因。该研究以贵州荷斯坦奶牛为试验动物,利用奶牛DGAT1基因序列设计引物,以RCR-单链构象多态性(PCR-SSCP)方法检测了奶牛DGAT1基因第8外显子的碱基突变。结果共检测到AA、AB和BB 3种基因型,基因型频率分别为0.5588、0.3824和0.0588,等位基因A和B的频率分别为0.7549和0.2451;该碱基突变对305d校正产奶量和乳脂率的影响均达到显著水平(P<0.05),乳蛋白率影响不显著(P>0.05);多重比较结果表明,AA和AB型对305d校正产奶量和乳脂率均显著高于BB型(P<0.05)。结果显示,DGAT1基因突变对贵州荷斯坦奶牛泌乳性状有较大的遗传效应,可用于其泌乳性状的分子标记辅助选择。

Diacyglycerol acyl-transferase 1 （DGAT1） was considered to be the key enzyme in controlling the synthesis rate of triglycerides. The DGAT1 gene was recently identified,and DGAT1 gene became a strong functional candidate gene for milk fat percentage in cattle. This study used Guizhou Holstein cows as experimental animals,the cow DGAT1 gene was cloned by polymerase chain reaction using PCR primers. PCR-single-strand conformation polymorphism （PCR-SSCP）assay was used to diagnose the DGAT1 exon 8.The results showed that three genotypes were found and the genotypic frequencies of AA, AB and BB were 0.5588,0.3824 and 0.0588,respectively. The gene frequencies of A and B were 0.7549 and 0.2451.The significant association of the gene mutation in DGAT1 exon 8 with 305 days corrected milk yield and milk fat percentage （P〈0.05）, and had no significant effect on the protein percentage in milk （P〉0.05）. LSD showed that the cows with AA and AB genotypes had higher tested 305 days corrected milk yield and milk protein percentage than those with BB genotype （P〈0.05）.The conclusion indicated that the gene mutation in DGAT1 had a great genetic effect on milking traits and could be a useful genetic marker for Guizhou Holstein breeding.