SCD1基因不同基因型的差异表达及与牛奶中脂肪酸组成的相关性

【目的】探索中国南方荷斯坦奶牛SCD1基因不同基因型的差异表达及与牛奶中脂肪酸组成的相关性。【方法】以同一奶牛养殖场的303头中国荷斯坦奶牛为样本，利用PCR-SSCP技术检测SCD1基因第5外显子878 bp位置的多态性，采用定量FQ-PCR技术初步检测3种基因型的相对表达量，并运用气相色谱技术分析牛奶中脂肪酸的组成。【结果】共检测到3种基因型，即CC、CT和TT，基因型频率分别为0.617、0.339和0.044，等位基因C和T的频率分别为0.787和0.213，仅发现CT表达量显著高于TT（P＜0.05）。CC、CT和TT在脂肪酸C4﹕0、C12﹕0、C17﹕0上存在显著差异（P＜0.05）；在脂肪酸C6﹕0、C8﹕0、C14﹕0、C15﹕0和c9t11CLA上，3种基因型间差异极显著（P＜0.01）。在总饱和脂肪酸含量上TT显著高于CC和CT（P＜0.05）。【结论】SCD1基因C878T位点的突变对中国荷斯坦牛SCD1基因不同基因型的表达和乳脂肪酸成分有较大的遗传效应。

Genotype and Gene Expression of SCD1 Gene Associated with the Content and Composition of Fatty Acid in Milk

【Objective】The effect of SCD1 different genotypes on gene expression and milk fatty acid composition was studied.【Method】Three hundred and three Chinese Holstein cows of a dairy farm were used to detect the polymorphism of the exon 5 of SCD1 gene using PCR-SSCP,and the relative gene expression was assayed by quantitative FQ-PCR,the milk fatty acid composition was assayed using the method of gas chromatography.【Result】One SNP,C878T,was detected,defining three genotypes,CC,CT and TT,with frequencies of 0.617,0.339 and 0.044,respectively.The allele frequencies of C and T were,respectively,0.787 and 0.213.Only the expression of CT genotype was significantly higher than TT genotype(P<0.05).Total saturated fatty acids of TT was significantly higher than CC or CT(P<0.05).There were highly significant differences in the fatty acid C6:0,C8:0,C14:0,C15:0 and c9t11CLA(P<0.01),and significant differences in the fatty acid C4:0,C12:0,C17:0 among these three genotypes(P< 0.05)【.Conclusion】The SNP C878T of SCD1 has a great genetic effect on the gene expression of SCD1 and the content of fatty acid in milk,it could be a useful genetic marker for milking trait in Chinese Holstein breeding.