Liu X, Guo X Y, Xu X Z, Wu M, Zhang X, Li Q, Ma P P, Zhang Y, Wang C Y, Geng F J, Qin C H, Liu L, Shi W H, Wang Y C, Yu Y
Key Laboratory of Agricultural Animal and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, P.R. China.
Genet Mol Res. 2012 Aug 16;11(3):2569-77. doi: 10.4238/2012.June.29.1.
DNA methylation is essential for adipose deposition in mammals. We screened SNPs of the bovine DNA methyltransferase 3b (DNMT3b) gene in Snow Dragon beef, a commercial beef cattle population in China. Nine SNPs were found in the population and three of six novel SNPs were chosen for genotyping and analyzing a possible association with 16 meat quality traits. The frequencies of the alleles and genotypes of the three SNPs in Snow Dragon beef were similar to those in their terminal-paternal breed, Wagyu. Association analysis disclosed that SNP1 was not associated with any of the traits; SNP2 was significantly associated with lean meat color score and chuck short rib score, and SNP3 had a significant effect on dressing percentage and back-fat thickness in the beef population. The individuals with genotype GG for SNP2 had a 25.7% increase in lean meat color score and a 146% increase in chuck short rib score, compared with genotype AA. The cattle with genotype AG for SNP3 had 35.7 and 24% increases in dressing percentage and 28.8 and 29.2% increases in back-fat thickness, compared with genotypes GG and AA, respectively. Genotypic combination analysis revealed significant interactions between SNP1 and SNP2 and between SNP2 and SNP3 for the traits rib-eye area and live weight. We conclude that there is considerable evidence that DNMT3b is a determiner of beef quality traits.
DNA甲基化对于哺乳动物的脂肪沉积至关重要。我们在中国一个商业肉牛品种雪龙牛中筛选了牛DNA甲基转移酶3b（DNMT3b）基因的单核苷酸多态性（SNP）。在该群体中发现了9个SNP，并从6个新的SNP中选择了3个进行基因分型，并分析其与16个肉质性状的可能关联。雪龙牛中这3个SNP的等位基因和基因型频率与其终端父本品种和牛相似。关联分析表明，SNP1与任何性状均无关联；SNP2与瘦肉颜色评分和肩胛小排评分显著相关，SNP3对牛肉群体的屠宰率和背膘厚度有显著影响。与基因型AA相比，SNP2基因型为GG的个体瘦肉颜色评分增加25.7%，肩胛小排评分增加146%。与基因型GG和AA相比，SNP3基因型为AG的牛屠宰率分别增加35.7%和24%，背膘厚度分别增加28.8%和29.2%。基因型组合分析显示，对于肋眼面积和活重性状，SNP1与SNP2之间以及SNP2与SNP3之间存在显著的相互作用。我们得出结论，有充分证据表明DNMT3b是牛肉品质性状的一个决定因素。
