从细胞色素b基因序列分析羚牛分子系统进化

目的分析羚牛分子系统进化,解决多年来关于羚牛分类地位及其与麝牛关系的争论。方法应用聚合酶链式反应(PCR)分别扩增羚牛、绵羊、山羊细胞色素b基因,并对其全序列(1140bp)进行测定。结合GenBank检索序列,对9种偶蹄类动物(麝牛、绵羊、羚牛等)、1种奇蹄类动物(斑马)的细胞色素b基因序列差异进行分析,并基于序列差异构建分子系统树。结果羚牛与羊亚科的动物亲缘关系最近(序列差异分别为9.085%和11.652%),与其他动物亲缘关系较远(序列差异为12.344%~23.333%),与麝牛的差异达到了13.658%。羚牛与绵羊分歧的时间约在360万年前,而与麝牛的分歧时间约在550万年前。结论将羚牛归入羊亚科较为合理,羚牛和麝牛形态和行为上很强的相似性可能是趋同进化的结果。

Analysis of cytochrome b gene of takin and its phylogeny

Aim To analyze takin's phylogeny in order to solve the argument about the relationship between takin and muskox.Methods The cytochrome b genes(1140bp) from takin,sheep and goat were amplified and sequenced.Analyzing the sequence divergence of 9 species of Artiodactyla and 1 specie of Perissodactyla,two phylogenetic trees were built based on the divergence.Some gene sequences were searched and obtained from Genbank.Results The genetic relationship between takin and the species of Caprine was found to be closer(9.085%~11.652% sequence divergence) than that between takin and other related animals(12.344%~23.333% sequence divergence).The sequence divergence between takin and muskox was 13.658%.The time when divergent phylogenetic event occurred for takin and sheep was about 3.6 million years ago,but for takin and muskox was about 5.5 million years ago.Conclusion Placing takin under Caprinae seems more reasonable.Similarities of takin and muskox in behavior and morphology might be attributed to convergent evolution.