四种实验用小型猪mtDNA控制区5＇端序列的比较研究

Comparative Research on the Sequence of 5＇ End of MtDNA D-loop Region of Four Breeds of Mini-pigs

目的测定西藏小型猪以及巴马小型猪、贵州香猪和五指山猪的mtDNA控制区5’端序列，比较研究其遗传变异和与国内家猪的亲缘关系。方法扩增四种小型猪的mtDNA控制区5’端，测序并进行所测序列多重比对，确定变异位点、单倍型，并建立亲缘关系树。结果与荣昌猪相比，西藏小型猪mtDNA控制区5’端侧翼区704bp，有20个变异位点，由此归纳出26个单倍型；其中有两种主体单倍型，三个转换位点（305，500，691）的碱基分别为t，a，a和c，g，g。巴马小型猪、贵州香猪和五指山猪mtDNA控制区5’端变异位点较少，分别只有4、4、3种单倍型。亲缘关系树的分析表明，西藏小型猪与其它三种小型猪有较近的亲缘关系。结论西藏小型猪群体存在遗传分化，与巴马小型猪、贵州香猪和五指山猪亲缘关系较近；巴马小型猪、贵州香猪和五指山猪遗传均一性较高，可能与长期的人工选择有关。

Objectives To analyze the sequence of 5＇ end ofmtDNA D-loop region of Tibet minipigs, Bama miniature pigs and Guizhou xiang pigs and WZS pigs, to investigate genetic differentiation and the phylogenefic relationship between mini-pigs and several other breeds of Chinese domesticated pigs. Methods The fragment of 5＇ end of D-loop region in four breed mini-pigs were amplified and sequenced, followed by being multiple alignment compared with each other, then variation sites and haplotype were made. Genetic relationship tree between mini-pigs and other China domestic pigs were established. Results Compared with Rongchang pig, 704bp sequence at 5＇ end of the Tibet mini-pigs D-loop had 20 polymorphic sites which deduced 26 haplotypes. There were two mainly haplotypes which have three transform sites at 305, 500 and 691, one is t, a, a, respectively; another is c, g, g, respectively. Bama miniature pigs, Guizhou xiang pigs and WZS pigs had 4, 4 and 3 haplotypes, respectively. Tibet mini-pigs had close relation with domestic pigs in southwest China by using phylogenetic tree. Conclusions There were genetic differentiation in Tibet mini-pigs colony and had a closely genetic relationships with southwest Chinese domestic pigs. Bama miniature pig and Guizhou xiang pig and WZS pig had less genetic differentiation that may be the results of artificial selection.