【摘要】 应用生物信息学方法对27种刺鳅属鱼类和中华刺鳅的线粒体COI基因序列片段进行了比较分析,结果表明:COI基因碱基组成偏倚明显,27种刺鳅属鱼类COI基因中,A+T含量(53.6%)明显高于G+C含量(46.4%);在中华刺鳅COI基因中,A+T含量(57.8%)也明显高于G+C含量(42.2%),这与大部分鱼类的COI基因序列研究结果一致。中华刺鳅与大多数刺鳅属鱼类均保持中等遗传距离(0.162～0.217),但与非洲坦噶尼喀湖特有的Mastacembelus albomaculatus的遗传距离较远,达到0.268,计算了27种和26种(剔除Mastacembelus albomaculatus)刺鳅属鱼类的平均遗传距离,分别为0.134和0.123。基于COI基因构建的系统发育树分析,27种刺鳅属(Mastacembelus)鱼类和中华刺鳅可以明显区分为3个类群,即以大刺鳅等大多数刺鳅属鱼类、中华刺鳅、Mastacembelus albomaculatus。研究结果支持中华刺鳅属于刺鳅科,同时建议重新整理刺鳅属。由NJ和MP法构建的系统发生树均提示,非洲坦噶尼喀湖特有的Mastacembelus albomaculatus是相对较古老的类群,刺鳅属鱼类可能起源于非洲,但这需要进一步更加全面的分子生物学分析。同时,大刺鳅和中华刺鳅保持相对较近的遗传距离,通过种间杂交,培育耐低温且营养高的新品种具有较大的可行性。更多还原

【Abstract】 The bioinformatics method was used to compare the COI gene sequence fragments of 27 species of Mastacembelus and Sinobdella sinensis. The results showed that the COI sequences of Mastacembelus presented the base preference. On average, the content of A+T(53.6%) was significantly higher than that of G+C(46.4%). The content of A+T in COI gene of Sinobdella sinensis(57.8%) was also significantly higher than that of G+C(42.2%). This was consistent with the COI gene sequences of most fish. The genetic distance was 0.162～0.217 between Sinobdella sinensis and most of the Mastacembelus fishes. However, the genetic distance from Mastacembelus albomaculatus, which was endemic to Lake Tanganyika in Africa, was relatively far, reaching 0.268. The average genetic distances of 27 and 26 species(excluding Mastacembelus albomaculatus) of the genus Mastacembelus were calculated, which were 0.134 and 0.123 respectively. Based on COI gene construction, phylogenetic tree analysis showed that 27 species of Mastacembelus and Sinobdella sinensis could be clearly divided into three groups, namely, most of the genus of Mastacembelus such as Mastacembelus armatus, Sinobdella sinensis and Mastacembelus albomaculatus. Our results supported the attribution of Sinobdella sinensis to Mastacembelidae, and we suggested a rearrangement of Mastacembelidae. Phylogenetic trees constructed by both NJ and MP methods suggested that Mastacembelus albomaculatus, endemic to Lake Tanganyika in Africa, was a relatively ancient group. The Mastacembelus may have originated in Africa. However, further and more comprehensive molecular biological analysis is needed. At the same time, it is feasible to breed new varieties with low temperature tolerance and high nutrition through interspecific hybridization because of the relatively close genetic distance between Mastacembelus armatus and Sinobdella sinensis.更多还原