从细胞色素b基因序列差异分析神农架白熊的系统进化关系

神农架白熊的分类地位从它被发现后就一直存在着争议。文章测定了神农架白熊一个个体的Cyt b基因从423~1 140共718 bp的序列, 结合亚洲黑熊(Selenarctos thibetanus)、美洲黑熊(Euarctos americanus)、马来熊(Helarctos malayanus)、棕熊(Ursus arctos)、北极熊(Thalarctos maritimus)、懒熊(Melursus ursinus)、眼镜熊(Tremarctos ornatus)、大熊猫(Ailuropoda melanoleuca)、小熊猫(Ailurus fulgens)、浣熊(Procyon lotor)同源DNA序列进行比较, 分析了碱基组成频率、替代数、变异位点、简约信息位点数、转换/颠换比率、相似指数和分化指数。用邻接法( NJ)和最大节约法(MP)构建了分子系统树, 得到了基本相同的拓扑结构。结果显示, 神农架白熊与亚洲黑熊的亲缘关系最近, 与大熊猫的亲缘关系较远。

A Molecular Phylogeny of Shennongjia White Bear Based on Mitochondrial Cytochrome b Gene Sequence

The phylogenetic relationship of Shennongjia white bear has been an open question. Total DNA was extracted and sequenced from hair and feces of Shennongjia white bear. Based on the partial Cyt b gene sequence obtained from the samples, the authors aligned them using the Clustal W software program. The MEGA software was used to analyze the divergences and base substitutions of the partial Cyt b gene among the 11 species: Shennongjia white bear, Selenarctos thibetanus, Euarctos americanus, Helarctos malayanus, Ursus arctos, Thalarctos maritimus, Melursus ursinus, Procyon lotor, Ailuropoda melanoleuca, Ailurus fulgens and Tremarctos ornatus. The phylogenetic trees constructed by multiple methods (NJ and MP) supported nearly the same topology. Our molecular results show that the sequence divergence between Shennongjia white bear and Asiatic black bear (Selenarctos thibetanus) is lower than that between other species.