深县猪mtDNA CytB基因的遗传多样性与母系起源研究

为探讨深县猪群体内的遗传多样性及母系起源分化,采用PCR直接测序法测定了40头深县猪的mtDNA CytB基因长1 140 bp片段的全序列,并结合GenBank已公布的15个猪种mtDNA CytB基因全序列,采用邻接法构建深县猪、部分其他地方猪种和引进猪种的系统发育树。结果显示,在1 140 bp长的序列中A、T、G、C的含量分别为25.93%、31.72%、28.90%及13.45%,其中A+T的含量(57.65%)高于G+C的含量(42.35%);共发现2个变异位点,无插入和缺失突变,全部为转换位点,其中简约信息位点2个,未发现单一信息位点。40条序列共定义了3种单倍型,单倍型多样性(HD)为0.312,核苷酸多样性(Pi)为0.00026,平均核苷酸差异数(K)为0.327。在深县猪mtDNA CytB基因全序列NJ进化树中,三种单倍型聚为同一分支,母系来源单一,与莱芜猪、大蒲莲猪等山东品种遗传距离较近。结果表明,深县猪群体内遗传多样性比较贫乏,与山东地区的华北型黑猪种群有更近的亲缘关系。

Study on Genetic Diversity and Maternal Origin of mtDNA CytB Gene in Shenxian Pigs

In order to investigate the genetic diversity and maternal origin differentiation in the pig population of Shenxian County, the full sequence of 1 140 bp fragment of the mtDNA CytB gene of 40 Shenxian pigs was determined by PCR direct sequencing, and combined with the mtDNA of 15 pig breeds published in GenBank. The complete sequence of CytB gene was constructed by using the adjacency method to construct phylogenetic trees of Shenxian pigs, some other local pig breeds and introduced pig breeds. The results showed that the contents of A, T, G and C in the 1140 bp sequence were 25.93%, 31.72%, 28.90% and 13.45%, respectively, and the content of A+T(57.65%) was higher than that of G+C(42.35%);2 mutation sites were found, no insertion and deletion mutations, all of which were transformation sites, of which 2 were simple information sites, and no single information site was found. A total of three haplotypes were defined for the 40 sequences, with a haplotype diversity(HD) of 0.312, a nucleotide diversity(Pi) of 0.00026, and an average nucleotide difference(K) of 0.327. In the complete sequence NJ phylogenetic tree of mtDNA CytB gene in Shenxian pig, the three haplotypes of Shenxian pigs were clustered into the same branch, and the maternal source was single, which was close to the genetic distance of Shandong varieties such as Laiwu pig and Dapulian pig. The results showed that the genetic diversity in Shenxian pig population was relatively poor, and it was closer to the North China black pig population in Shandong.