绵羊味觉受体第一家族基因外显子多态性分析

Polymorphism Analysis of Taste Receptor Family 1 Member Gene Exons in Sheep

为了探讨绵羊味觉受体第一家族(taste receptor family 1member,T1R)基因外显子多态性及其基因型在乌珠穆沁羊和湖羊群体中分布的差异性,试验采用DNA池直接测序及飞行时间质谱(MALDI-TOFMS)法对中国蒙古系两个绵羊品种共172个个体T1Rs基因外显子的遗传变异情况进行分析,利用生物信息学软件预测多态位点对T1Rs基因mRNA二级结构和蛋白质二级结构的影响。结果表明,在两个群体的T1R家族基因中筛查到9个SNPs。独立性卡方检验显示有5个多态位点基因型的分布在两个绵羊群体中存在显著性差异(P<0.05),分别为TAS1R1基因上的SNP2,TAS1R2基因上的SNP4、SNP7和SNP8,TAS1R3上的SNP10,其中,SNP2、SNP7和SNP10为同义突变;SNP2和SNP10导致相应基因mRNA二级结构和最小自由能的改变,而SNP7仅导致TAS1R2基因最小自由能发生改变;SNP4和SNP8为错义突变,分别导致TAS1R2蛋白质中第379位天冬酰胺变为丝氨酸和第701位苏氨酸变成蛋氨酸,且突变前后受体蛋白的二级结构均发生改变。

This study was aimed to investigate the distribution of genetic polymorphism of taste receptor family 1member（T1R）gene between Ujimqin sheep and Hu sheep.DNA pools direct sequencing method and MALDI-TOFMS method were used to analyze genetic variation of T1 Rgenes in 172 sheep of two Chinese sheep strains of Mongolian,and bioinformatics software predicted what impact polymorphic loci had to mRNA and protein secondary structure of T1 R gene.The results showed that 9SNPs were screened in T1 Rgene of two groups.Chi-square test for independence was taken to find the genotypes of the 5SNPs which were significantly different between two sheep population（P〈0.05）,SNP2 located in TAS1R1 gene,SNP4,SNP7 and SNP8located in TAS1R2 gene,SNP10located in TAS1R3 gene.SNP2,SNP7 and SNP10were silent mutations.SNP2 and SNP10lead to corresponding gene mRNA secondary structure and the minimum free energy change,while the SNP7 only lead to the minimum free energy changes.SNP4 and SNP8were missense mutations,the two missense mutations respectively led to asparagine（Asn）into serine（Ser）,threonine（Thr）into methionine（Met）,and according to online software forecast,the protein secondary structure of TAS1R2 gene all changed in mutations before and after.