为探讨沼泽型水牛与河流型水牛之间的线粒体D-loop区差异与进化关系，对26头广西本地水牛、8头贵州贵阳水牛、11头广西水牛与河流型水牛杂交后代、9头尼里拉菲和12头摩拉水牛（共5个群体66头水牛个体）的线粒体全长D-loop序列进行了扩增测序分析.结果发现66头水牛912 bp的D-loop多重序列比较有147个多态位点，形成58个单体型，沼泽型水牛与河流型水牛单体型明显分成2簇.以牛为外群构建的单体型进化树显示，沼泽型与河流型水牛分成明显2大支，河流型水牛聚成1支，而沼泽型水牛内部又分成2个侧支.通过Median joining network分析亦发现3个不同的簇，与进化树分析结果一致.对该区碱基错配分布分析表明，水牛群体在历史上发生2次独立的群体扩增事件.为进一步验证试验结果，从GenBank下载了211条水牛D-loop序列与笔者研究获得的序列整合分析，在共有序列878 bp区域中，包含了158个多态位点和129个单体型，以牛为外群的进化树分析与单体型网络分析表明，沼泽型水牛分成2簇，所有的河流型水牛聚集成紧密的1簇.碱基错配分布分析结果呈现2个明显的峰，进一步推断水牛群体在历史上发生过2次较大的群体扩增事件.综合上述研究结果推断，沼泽型水牛与河流型水牛来自不同的家养化事件，沼泽型水牛起源于中国，其祖先可能存在2个基因池.
To investigate the polymorphism of mitochondrial D-loop in water buffalo, the entire mitochondrial D-loop region of 66 water buffaloes of five different groups were analyzed, and 58 mitochondrial haplotypes with 147 polymorphic sites were detected. The haplotypes of swamp buffaloes and river buffaloes formed two different clusters, based on the phylogenetic trees constructed with ML method using bovine D-loop sequences as outgroup. The trees showed that swamp buffaloes and river buffaloes belong to two distinctly different clusters, and two small clusters were observed in the swamp cluster among the three. By median joining network analysis, three different clusters were also founded, one high diverged clusters between swamp and river buffalo, and two little clusters appeared in the whole swamp cluster. The mismatch distribution analysis showed that there might have been two different indepent population expansion events in the evolution history of buffaloes. Pooled with 211 released D-loop sequences of Genbank, and 129 haplotypes with 158 polymorphic sites were detected in 878 bp multi-aligned region. The phylogenetic tree and median joining network analysis also showed that there were three clusters in all sampled buffaloes, two swamp buffalo’s clusters and one high diverged river swamps. Two obviously wave crests appeared in the mismatch distribution analysis, which meaned that there might have been two different population expanding events in water buffaloes. Based on the above results, it could be predicted that river and swamp buffaloes decented from two different domestication events, and there were at least two ancestor gene pools in the domestication of swamp buffaloes.