5个绵羊品种CAST基因多态性及其与肉品质的相关性

摘要

In order to study the relationship between the CAST gene polymorphism and meat quality of 5 sheep breeds ( Gansu alpine fine wool sheep, Small tail han sheep, Tibetan, Mongolian sheep and Tan-sheep which were fed in a typical farming mode of Gansu province) in Gansu Province at the molecular level and to explore the possibility of improving the quality of sheep meat by using CAST as a candidate gene, the polymorphism of intron 3 of CAST gene was detected by PCR-SSCP in 5 sheep breeds, and the association between CAST gene polymorphism and meat quali-ty in 9-month-old sheep was analyzed. The results showed: compared with allele A, two mutations were detected which included G62T and C110T in allele B while only C92T was detected in allele C. The mutations formed AA, AB, BB and AC genotypes. Experimental results showed that 5 sheep breeds were in non-Hardy-Weinberg equilibri-um state. Population genetic polymorphism analysis showed that the polymorphism information content ( PIC) of the 5 sheep breeds was moderate. The association analysis showed that the water loss rate of AC genotype was significantly higher than those of others (P<0. 05), the shear forcer of AC was significantly lower than those of other three geno-types (P<0. 05). Genotype analysis of different sheep breeds showed that the water loss rate of AC genotype was significantly higher than other three genotypes ( P<0. 05 ) , and the shear stress of AC genotype was significantly lower than other genotypes(P<0. 05) except Mongolia sheep. The mutation locus had no significant influence on eye muscle area. These associations showed CAST gene could be used as a candidate gene for marker-assisted selection of sheep meat performance and meat quality.%为从分子水平研究甘肃境内典型养殖模式下甘肃高山细毛羊、小尾寒羊、藏羊、蒙古羊和滩羊5个绵羊品种的CAST基因多态性与肉品质的相关性，探讨以CAST为候选基因，提高绵羊肉品质的可能性。采用PCR-SSCP技术对5个绵羊品种的CAST基因内含子3多态性进行检测，并就CAST基因多态性与9月龄肉品质进行相关性分析。根据比对结果发现，与等位基因A相比，等位基因B发现G62T以及C110T突变，等位基因C发现C92T突变，形成AA、AB、BB和AC 4种基因型；经检验表明，5个绵羊品种均处于非 Hardy-Wein-berg 平衡状态；群体遗传多态性分析表明，5个绵羊品种的多态信息含量均为中度多态；关联分析表明，5个绵羊品种 CAST基因变异位点的4个基因型间失水率AC基因型显著高于其他基因型（ P＜0.05），对于剪切力AC基因型显著低于其他3种基因型（P＜0.05）；不同绵羊品种间基因型分析表明，对于5个绵羊品种AC基因型的失水率显著高于其他3种基因型，除蒙古羊外，AC基因型的剪切力显著低于其他基因型；变异对眼肌面积没有显著性影响。这些关联说明CAST 基因可作为候选基因用于绵羊产肉性能和肉品质的分子标记辅助选择。