三个国外猪种线粒体COXⅠ基因SNPs筛选及序列分析

SNPs detection and sequential analysis among pig breeds of foreign based on mt DNA COXⅠ gene

本研究对三个国外猪种216个样本(大白猪、长白猪和杜洛克)mt DNA COXⅠ基因构建混合池,利用直接测序技术获得3个猪种COXⅠ基因的序列,进行SNPs筛选及序列分析,并采用MEGA 6.0分析软件基于Kimurk双参数模型应用邻接法构建系统发生树。结果表明,3个猪种mt DNA COXⅠ基因序列共存在16个突变位点,且有3个突变位点为3个猪种共有。长白猪与杜洛克猪的多态性较丰富,含有13个相同位点的突变,核苷酸的转换数(si)和颠换数(sv)的比值(R)分别为12和15,序列替换远未达到饱和。系统进化树和遗传距离分析显示长白猪及杜洛克亲缘关系较近,先聚为一支,再与大白猪、及野猪聚为一支。大白猪与中国东北地区野猪聚为一支,这可能与大白猪在培育过程中亲本遗传背景较复杂有关。本研究在一定程度上为了解大白猪的育成史及合理利用国外猪种提供了理论依据。

This study was based on the Mitochondrial DNA COX I （mtDNA COX I） gene of 3 pig breeds （Large White pig, Landrace pig and Duroc pig）. The mtDNA COX I gene sequences obtained from 3 pig breeds were sequenced and analyzed. Besides, we constructed phylogenetic tree by using MEGA 6.0 analysis software and neighbor joining method based on Kimurk two parameter model. The results show that there were 16 mutations in sequences of COX I （1545 bp）, and 3 mutant site were found in 3 pig species. Landrace pig and Duroc pig are abundant in polymorphism（13 same mutation sites）, and the ratios（R） of nucleotides＇ conversion number（si） and Transition number（sv） were 12 and 15 which proved Sequence substitution were far from saturation. Phylogenetic tree and genetic distance analysis showed close genetic relationship of Landrace and Duroc, first clustered into one clade, with large white boars, and clustered into one clade. Large white and northeast wild boar China clustered into one, may be related to large white have a complexed parents genetic background in the breeding. To some extent, this study provides a theoretical basis for the understanding the breeding history of large white and rational utilization of local pig breeds.