湖羊、东湖杂种羊POMC基因外显子3单核苷酸多态性及其与生长性状的关联分析

阿黑皮素原(Pro-opiomelanocortin, POMC)在动物采食和能量平衡调控中发挥重要作用, 文章对绵羊POMC基因外显子3进行扩增和测序, 筛选多态性位点, 并分析多态位点与湖羊和东弗里生×湖羊杂种羊生长性状的相关性。测序后发现湖羊POMC基因外显子3有2个单碱基突变(g.273 T/C和g.456 G/A), 根据273位点处发生的T/C突变, 建立PCR-RFLP分析方法, 并对162只湖羊和130只东湖杂种羊进行检测分析。结果发现, 在湖羊群体中检测到TT(0.469)、TC(0.438)和CC(0.093)3种基因型, 而在东湖杂种羊群体中仅检测到TT(0.754)和TC(0.246)两种基因型。POMC基因外显子3的273位点多态性与生长性状的相关性研究结果显示：湖羊群体中CC基因型个体的2月龄断奶重、4月龄尻高及TC基因型个体4月龄体长和管围均显著高于TT型个体(P<0.05); CC基因型个体的4月龄重、6月龄重极显著高于TT和TC基因型个体(P<0.01); CC基因型个体的4月龄体高和体长极显著高于TT型个体(P<0.01), 且显著高于TC基因型个体(P<0.05)。此外, CC型个体的管围极显著高于TT基因型个体(P<0.01)。东湖杂种羊群体中TC基因型个体的2月龄断奶重、4月龄重及4月龄体高、体长、胸深和管围都显著高于TT型个体(P<0.05), TC型个体的6月龄重极显著高于TT型个体(P<0.01)。研究结果表明, POMC基因外显子3与绵羊生长性状相关, C等位基因对体重及体尺性状的增加更有利。该结果为进一步探讨POMC基因作为绵羊生长性状的辅助选育标记奠定了基础。

Single nuclear polymorphisms in exon 3 of POMC gene and the asso-ciation with growth traits in Hu sheep and East Friesian × Hu crossbred sheep

Pro-opiomelancortin (POMC) plays important roles in the regulation of food intake and energy expenditure. The sheep exon 3 of gene POMC was amplified and sequenced by screening the DNA pools to select single nuclear polymorphisms and analyze the association with the growth traits. Two silent SNP mutations (g.273 T/C and g.456 G/A) in Hu sheep were identified. PCR-restriction fragment length polymorphism (RFLP) was used to test the g.273 T/C and the association between the g.273 T/C polymorphism and some growth traits was analyzed in Hu sheep (n=162) and East Friesian × Hu crossbred sheep (n=130). The results showed that three genotypes, TT, TC and CC, were detected in Hu sheep with the frequencies of 0.469, 0.438 and 0.093, respectively. Two genotypes, TT and TC, were detected in East Friesian × Hu cross-bred sheep with the frequencies of 0.754 and 0.246, respectively. The association analysis showed that in Hu sheep the two-month weaning weight, four-month rump height of genotype CC and the four-month body length, cannon circumfer-ence of genotype TC were significantly higher than those of genotype TT (P<0.05); the four- and six-month weight of geno-type CC were significantly higher than those of genotypes TT and TC (P<0.01); the four-month body height and body length of genotype CC were significantly higher than those of genotypes TT (P<0.01) and TC (P<0.05); the four-month cannon circumference of CC genotype was significantly higher than that of TT genotype (P<0.01). In East Friesian × Hu crossbred sheep the two-month weaning weight, four-month weight, body height, body length, chest depth and cannon cir-cumference of genotype TC were significantly higher than those of genotype TT (P<0.05); the six-month weight of geno-type TC was significantly higher than that of genotype CC (P<0.01). In conclusion, the exon 3 of gene POMC was associ-ated with growth traits, and C allele was beneficial to the increase of body weight and body size traits of sheep, which po-tentially afford a good foundation for further study on POMC gene as aided breeding markers for growth traits in sheep.