A-FABP基因5′侧翼区多态性及其与秦川牛肉用性状的关联分析

Genetic Polymorphisms within 5′Flanking Region of Bovine A-FABP Gene and Its Relationships with Beef Performance Traits in Qinchuan Cattle

本研究通过对牛脂肪型脂肪酸结合蛋白(A-FABP)基因5′侧翼区的1441bp序列进行SNPs检测,结果在转录起始位点上游-389bp处发现T→C突变,进而利用PCR-SSCP的方法在秦川牛、南阳牛、鲁西牛、夏南牛和郏县红牛共5个牛群体中进行个体基因型分析,结果发现3种基因型,分别命名为AA、AB和BB。χ2检验表明,除秦川牛外其它各品种在该基因座均处于Hardy-Weinberg平衡状态(P>0.05)。基因型与秦川牛肉用性状的关联分析发现,AB基因型个体的宰前活体质量、胴体质量、含水率均显著低于AA和BB基因型个体(P<0.05),AA和BB基因型个体之间差异不显著;BB基因型个体大理石花纹等级极显著优于AB基因型个体(P<0.01),显著优于AA基因型个体(P<0.05)。推测这一位点可能是影响牛肉大理石花纹及含水率的主效QTL或与之紧密连锁,可尝试做为肉牛肉质性状的候选分子标记。

The sequence of 1 441 bp from 5′flanking region of A-FABP gene was sequenced. The sequencing results showed only one SNP, namely -389（T/C）, then the genotypes of five native cattle breeds（Qinchuan cattle, Nanyang cattle, Luxi cattle, Jiaxian Red cattle and Xia′nan cattle） in China were examined by PCR-SSCP. The SNP was detected in each group and devided into three genotypes： AA, AB and BB. χ2 test indicated that this polymorphism site fit Hardy-Weinberg equilibrium（P0.05）in five native cattle breeds. The study of relationships between some beef performance traits and genotypes in Qinchuan cattle showed that slaughter weight, carcass weight, moisture content of individuals with genotype AB were significantly lower than that of individuals with genotype AA and BB （P0.05）, but no significant difference between AA and BB genotypes. The marbling score of individuals with genotype BB was very significantly better than that of individuals with genotype AB（P0.01）, and significantly better than that of individuals with genotype AA（P0.05）, but no significant difference between AB and AA genotypes. The results indicate that this locus is a probable major QTL affecting marbling score and moisture content or tightly links to those genes affecting beef performance traits, it could be a candidate molecular marker for the beef cattle breeding.