早胜牛及其杂交类群 IGF-Ⅱ基因多态性与肉用性状关联分析
Association Analysis between Polymorphism of IGF-Ⅱ Gene in Exon 2 and Beef Performance Traits in Zaosheng Cattle and Hybrid Groups

为研究 IGF-Ⅱ 基因多态性对胴体性状和肉质性状的影响，采用PCR-SSCP和DNA测序技术检测早胜牛及其杂交类群（南德温×早胜牛杂交一代、安格斯×早胜牛杂交一代） IGF-Ⅱ 基因第2外显子的遗传多态性，分析不同基因型与肉用性状的相关性。结果表明，检测到1个SNPs (T116C)，等位基因E和基因型EF频率分别为0.56和0.40，为优势等位基因和基因型；相关分析显示，屠宰率和优质肉块占宰前活质量比例FF型显著高于EE和EF型，净肉率EE型显著高于FF和EF型，背膘厚度FF和EE型都显著高于EF型，剪切力FF型显著低于EE和EF型。以上结果说明， IGF-Ⅱ 基因第2外显子可以作为早胜牛肉用方向选育的有效分子标记。
In order to study polymorphism of IGF-Ⅱ gene (Insulin-like growth factor-Ⅱ ) and its influence with characteristics of carcass and meat quality traits. PCR-SSCP and DNA sequencing technologies were conducted to detect heredity polymorphism of IGF-Ⅱ gene in exon 2 with Zaosheng cattle (Bos taurus) and hybrid groups(Hybrid of South Devon with Zaosheng cattle, hybrid of Angus with Zaosheng cattle), and analyze the correlation of different genotypes with beef performance traits.The results indicated that there was a base mutation at c. 116 T > C of exon 2, which leaded to three genotypes such as EE, EF and FF. The alleles E with the frequency of 0.56 and genotype EF with the frequency of 0.40,were the highest. Before slaughter of FF genotype, dressing percentage and proportion of high quality meat in live mass were significantly higher than that of EE genotype and EF genotype,percentage of net meat of EE genotype was significantly higher than that of FF and EF genotype, Backfat thickness with FF genotype and EE genotype were significantly higher than that of EF genotype, shear force with EE genotype and EF genotype were significantly higher than that of FF genotype. Therefore these results suggested that the exon 2 mutation of IGF-Ⅱ gene could be maker to beef performance breeding with Zaosheng cattle.