青海湖地区狗獾分类地位和狗獾属进化历史探讨

The taxonomic status of badgers in the Qinghai Lake area and evolutionary history of Meles

本研究选择线粒体细胞色素b(cytochrome b,Cyt b)和控制区(control region,CR)片段作为分子标记,探讨了青海湖地区狗獾(Meles sp.)的系统发育地位和狗獾属分歧时间。研究结果支持目前将狗獾属分为4个种的结论。Cyt b和CR片段序列拼接后总长1,652 bp,23条序列共定义了21个单倍型。研究结果表明欧亚大陆狗獾分为东西两个支系,每个支系进一步分为两个种:东部支系包括亚洲狗獾(M.leucurus)和日本狗獾(M.anakuma);西部支系包括欧洲狗獾(M.meles)和西南亚狗獾(M.canescens)。贝叶斯树和单倍型网络关系图都支持青海湖地区狗獾属于亚洲狗獾。分歧时间的估算结果与古生物学证据相符,东部支系和西部支系在2.24 Ma左右产生分歧,西南亚狗獾在1.27Ma左右从欧洲狗獾分出,而日本狗獾和亚洲狗獾的分化时间为0.99 Ma左右。

To investigate the phylogenetic status of badgers（Meles sp.） in the Qinghai Lake area and to estimate the divergence time within Eurasian badgers, the cytochrome b gene and the partial control region（CR） of mitochondrial DNA were examined as genetic markers. Our results indicated that Meles is divided into four species. Twenty one haplotypes were identified in 23 combined sequences（1,652 bp） of Cyt b and CR sequences. Results showed that Eurasian badgers were clearly divided into two major lineages： one of Western lineage, composed of badgers from Europe and Southwest Asia, and the other of Eastern lineage, composed of badgers from North and East Asia（including Japan）. Furthermore, the Bayesian tree and the haplotype network indicated that the badgers in the Qinghai Lake area are Asian badgers（M. leucurus）. The estimated divergence time was consistent with palaeontological evidence. The first split between the Western lineage and Eastern lineage occurred approximately 2.24 Ma. After the separation, the Southwest Asia clade split from Europe approximately 1.27 Ma and the Japan clade split from continental Asia approximately 0.99 Ma.