大白猪及巴马香猪GHRH基因的SNPs筛选及其与体尺的相关性分析

Screening of SNPs in GHRH Gene between Large White Pigs and Bama Xiang Pigs and Its Correlation with Body Size Traits

为了解影响猪生长和体尺的重要候选基因(GHRH基因)多态性与猪体尺的相关性,选取大白猪为大型猪的代表,巴马香猪为小型猪的代表,利用测序法筛查了两猪种间GHRH基因上存在的SNPs,统计了各个SNP在2个猪种的基因型频率及等位基因频率,然后基于基因型频率对每个SNP与猪体型的相关性进行分析,并将筛选到的与猪体型相关的SNPs进行连锁不平衡及单倍型分析。结果表明:共有7个SNPs存在于两猪种间,分别为g.1874A>C、g.2276A>G、g.4165C>-、g.4238T>C、g.8079I>-(GTGCTGGCGTGAG缺失)、g.8114A>G及g.8178A>G,且这些SNPs均与猪体尺性状显著相关,其中g.2276A>G和g.4165C>-存在连锁效应,并且大白猪形成的优势单倍型为AC,而巴马香猪为G-型,单倍型频率在两猪种间存在极显著差异(P<0.001);位于基因内含子4的3个位点(g.8079I>-、g.8114A>G及g.8178A>G)在大白猪中形成的单倍型为-GA,而巴马香猪为IAG,单倍型频率在两猪种间存在极显著差异(P<0.001)。这说明猪GHRH基因上存在的SNPs与猪体尺相关,可作为猪种遗传性状及育种的筛选标记,将为提高养猪经济效益及猪育种提供理论依据。

GHRH gene is considered as an important candidate gene affecting pig growth and body size. To analyze the relationship between polymorphisms of GHRH gene and pig body traits,Bama Xiang pigs,as a representative of miniature pigs,were used to screen SNPs in the GHRH gene,while Large White pigs were selected as large pigs. Genotype frequency and allele frequency of the two pig breeds were counted according to the sequence results,then the correlations between each SNP and the pig body were determined based on genotype frequency and further defined by linkage disequilibrium and haplotype analysis. The results showed that 7 SNPs( g.1874 A>C,g.2276 A>G,g.4165 C>-,g.4238 T>C,g.8079 I >-( GTGCTGGCGTGAG delete),g.8114 A >G and g.8178 A >G) were detected in the two pig breeds and these SNPs are all significantly associated with the body size traits of pigs,in which g. 2276 A >G and g. 4165 C >-had a chain effect,and the dominant haplotype formed by Large White pigs was AC,while that of Bama Xiang pigs was G-type. The haplotype frequency was significantly different between the two pig breeds( P< 0. 001). The haplotype formed in Large White pigs at the three loci of gene intron 4( g. 8079 I >-,g. 8114 A > G and g.8178 A>G) was-GA while that of Bama Xiang pigs was IAG haplotype,and the haplotype frequency was significantly different between the two pig breeds( P<0. 001). The results indicate that the SNPs present in the pig GHRH gene are associated to the pig body size,and can be used as a screening marker for the genetic traits and breeding of pigs. These data will provide a theoretical basis for improving the economic benefits of pig breeding.