中文摘要：

本研究旨在分析mtDNA ND4基因在中国西南马的遗传多样性。对中国西南马6个品种（类群）142个个体的线粒体DNA ND4基因部分序列进行PCR-SSCP和序列分析。结果表明,拼接后的西南马mtDNA ND4基因序列大小为679 bp,A＋T含量（55.7%）高于G＋C含量（44.3%）。共检测到11个核苷酸变异位点,这些变异位点可归纳为6种单倍型。核苷酸平均多样度为0.638%,表明受试西南马mt DNA遗传多样性并不十分丰富。对各单倍型进行聚类分析,结果提示中国西南马起源于2个母系祖先。

英文摘要：

This experiment is aimed to analyze mitochondrial DNA ND4 gene genetic polymorphism of Southwest horse in China. A partial fragment of mitochondrial DNA ND4 gene was sequenced and analyzed by PCR-SSCP for 142 individuals from 6 Southwest horse breeds in China. The results showed that the spliced sequence of mtDNA ND4 gene of Southwest horse was 679 bp, and the content of A＋T（55.7%） was higher than that of G＋C （44.3%）. 11 mutational sites were detected and all of these sequence polymorphic sites were sorted into 6 haplotypes. The average nucleotide diversity was 0. 638%, and the genetic polymorphism of mtDNA of tested Southwest horse was not abundant. The cluster analysis of these haplotypes suggested that Southwest horse in China originated from two maternal ancestors.