延边黄牛黑皮质素受体-4基因多态性及其与肉质性状的相关性分析

摘要

试验旨在探索调控肉牛脂肪沉积的关键基因对肉质性状的影响,筛选影响肉牛育肥性状的候选基因.本研究以157头24月龄、体重相近的延边黄牛为研究对象,利用PCR扩增直接测序的方法,分析了延边黄牛黑皮质素受体-4(melanocortin-4 receptor,MC4R)基因的SNPs及其与肉质性状的相关性.结果发现,延边黄牛MC4R基因在1069 bp处存在C→G突变,导致L(亮氨酸)转变为V(缬氨酸),引起蛋白质二级结构在166、243、280位氨基酸处出现α螺旋、β折叠丢失,导致三级结构中β转角的空间位置改变.经关联分析表明,该位点与延边黄牛背膘厚、亮度、黄度都存在不同程度的相关,其中GG基因型背膘厚与屠宰后黄度(3 d)显著高于CC和CG基因型(P<0.05);GG、CG基因型屠宰后亮度显著高于CC基因型(P<0.05).说明该位点与延边黄牛肉质性状存在显著相关,该突变位点可作为潜在的分子标记.%In order to explore the effects of the key gene of regulating cattle fat deposition on meat quality traits,screening candidate gene which affect beef fattening traits.This study employed 157 cattles (24 months old)with similar weight as research object,analyzed the correlation be-tween SNPs of MC4R gene and meat quality traits in Yanbian Yellow cattle by PCR direct se-quencing method.The results indicated that the mutation site of C→G had been found in MC4R gene 1069 bp,which resulted in L (leucine)translated into V (valine).Protein secondary struc-ture lost α-spiral and β-fold at the 166,243 and 280 amino acid position,which resulted in the changes of spatial position ofβ-turns in tertiary structure.This site showed different degrees cor-relation with backfat thickness,lrightness,yellowness of Yanbian Yellow cattle.The backfat thickness and yellowness (3 d)of GG genotype were significantly higher than CC and CG geno-types (P <0.05).The lrightness of CC and CG genotypes were significantly higher than CC gen-otype (P <0.05).These results declared that the site had remarkably correlatived with Yanbian Yellow cattle relevant economic traits,and the mutation site could be used as a potential molecu-lar marker.