秦川牛TNFSF11基因多态性及与体尺性状的相关性

摘要

为研究秦川牛TNFSF11基因多态性及其与秦川牛体尺性状的相关性,以399头同等饲养条件下的18～24月龄健康秦川母牛为研究对象,采用PCR-RFLP技术结合DNA测序技术检测TNFSF11基因的SNPs位点,并将其与秦川牛体尺性状进行关联分析.结果表明,DNA测序发现在TNFSF11基因第3内含子即34 080 bp处(C331区域)和第3内含子34 096 bp处(C332区域)分别发生C→T突变和T→C突变；PCR-RFLP分析发现,秦川牛TNFSF11基因C331区域经创造酶切位点后可以被限制性内切酶HincⅡ特异切割为有GG、GH和HH3种基因型,C332区域可以被内切酶BseLⅠ特异切割为MM、MN和NN 3种基因型；与测序结果比对显示,秦川牛TNFSF11基因C331、C332各酶切基因型与测序结果显示相一致.卡方检验显示,C331位点在所检测牛群中处于Hardy-Weinberg平衡状态(P＞0.05),而C332位点则处于Hardy-Weinberg极度不平衡状态(P＜0.01)；且C331处GH基因型为优势基因型,G等位基因为优势等位基因,处于中度多态状态；C332处基因型MM为优势基因型,M等位基因为优势基因,处于中度多态状态；关联分析表明,C331位点不同基因型个体间在腰高、腰角宽和胸围方面差异显著(P＜0.05),C332位点在体斜长和腰高方面差异显著(P＜0.05).经连锁不平衡检测发现,两位点存在一定的连锁特性(r2=0.213),将两突变位点进行单倍型分析可知,HHMM基因型各性状均显著高于其他基因型组合,且多标记位点的组合效应值高于单标记位点.说明TNFSF11基因对秦川牛体尺性状有显著的影响,可以作为秦川肉牛新品系培育早期选择的候选基因,其中组合HHMM可能是影响秦川牛体尺胴体性状的最佳基因型组合,在选育中应加大其选择力度.%This research studied on the polymorphisms of bovine TNFSF11 gene and their associations with body measurements in Qinchuan cattle. We employed PCR-RFLP and DNA sequencing to detect polymorphisms in bovine TNFSF11. 399 Qinchuan heifers with 18 and 24 months old -were selected to analyze the polymorphisms with their body measurement traits. Two SNPs in bovine TNFSF11 : SNP34080(C→T mutation), named as C331 ;SNP34096(T→C mutation) , named as C332 were identified. After PCR-RFLP analyzing, the C331 site had three genotypes(GG/GH/HH) with restriction enzyme-Hinc Ⅱ. And C332 site also had three genotypes (MM/MN/NN) with restriction enzyme-BseL I . All the genotypes were coincided with the consequences of DNA sequencing. Moreover, χ2 test showed the C331 site was in agreement with the Hardy-Weinberg equilibrium (P＞0. 05) , C332 site was significantly deviated from Hardy-Weinberg equilibrium (P＜C0. 01) in the detected Qinchuan cattle populations. In C331site, GH genotype was preponderant genotype, G allele was preponderant allele, and it belonged to intermediate genetic diversity. In C332 site, MM genotype was preponderant genotype, M allele was preponderant allele, and it also belonged to intermediate genetic diversity. Association analysis in C331 site showed individuals with different genotypes had significant differences on hip height, hip width and chest circumference (P＜0. 05) , while in C332 site individuals with different genotypes had significant differences on body length and hip height (P＜0. 05). After linkage disequilibrium analysis, it had linkage between these two sites. The results of haplotype analysis with combining the two loci showed body measurement traits of combined genotype HHMM were significantly higher than those of the other kinds of combinations. And the effect size of multi-loci combinations markers were higher than those of single-marker loci. These results provided evidence that TN-FSF11 gene had a significant effect on body measurement traits in Qinchuan cattle populations, thus, it could be a candidate gene in the breeding of Qinchuan beef cattle. Additionally, the combined genotype HHMM genotype should be selected as a molecular marker for beef cattle breeding as its superior performance on beef cattle body measurement traits in Qinchuan cattle populations.