5个绵羊品种MC4R基因多态性及其与生长性状的相关性分析

Analysis of MC4R Gene Polymorphism and Its Correlation with Growth Traits in Five Sheep Breeds

本研究以甘肃境内具有良好适应性的藏绵羊、蒙古羊、甘肃高山细毛羊和滩羊为研究对象,以甘肃外来品种小尾寒羊为对照,利用SSCP技术对5个绵羊品种的MC4R基因进行多态性检测分析,测序确定多态位点,通过与初生重、1月龄、3月龄、6月龄和9月龄生长性能相关分析,结果发现:MC4R基因在5个绵羊品种上均具有多态性,共检测到2个等位基因(G和A),3种基因型(GG,GA和AA);测序结果显示,在MC4R基因第1外显子的306 bp处发生单个碱基突变(G→A);相关性分析表明,MC4R基因型对5个绵羊品种的1月龄、3月龄和6月龄的体重有显著影响(p<0.05),且GA杂合型个体体重显著大于AA纯合型个体体重,但对初生重与9月龄的体重无显著影响(p>0.05);基因型效应对1月龄、3月龄、6月龄、9月龄的体长、体高、胸围均无显著影响(p>0.05)。研究认为MC4R基因可以作为选择甘肃地方绵羊品种生长性状的候选标记基因,小尾寒羊可以作为甘肃境内开展杂交生产及新品种培育的选择。

In this research,Tibetan sheep,Mongolian sheep,Gansu alpine fine wool sheep and Tan sheep with good adaptability in Gansu province were selected as the object of study,and the foreign breeds of Gansu small tail Han sheep were used as control.The polymorphism of MC4 R gene in 5 sheep breeds was detected by SSCP,and the polymorphism of MC4 R gene in 5 sheep breeds was detected by PCR.The polymorphic loci were determined by sequencing.The results showed that the polymorphism of MC4 R gene was found in 5 sheep breeds by correlation analysis with birth weight,1 month old,3 months old,6 months old and 9 months old growth performance.A total of two alleles(G and A),genotypes(GG,GA and AA),sequencing showed a single base mutation at 306 bp in exon 1 of the MC4 R gene.The correlation analysis showed that there was a single base mutation in the306 bp of exon 1 of the MC4 R gene.MC4 R genotype had a significant effect on body weight of 5 sheep breeds at1 month,3 months and 6 months,and the weight of GA heterozygous individuals was significantly higher than that of AA homozygous ones(p<0.05).However,it had no significant effect on the birth weight and the body weight of9 months old(p>0.05).Genotype effect had no significant effect on body length,height at the withers and chest girth at 1 month,3 months,6 months and 9 months old(p>0.05).It was suggested that MC4 R gene could be used as a candidate marker gene for the selection of growth traits of Gansu local sheep breeds,and small tail Han sheep could be used as a selection for cross production and breeding of new breeds in Gansu Province.