Data from: Genetic relationships of extant brown bears (Ursus arctos) and polar bears (Ursus maritimus)

Polar bears (Ursus maritimus) and brown bears (Ursus arctos) are closely related species for which extensive mitochondrial and nuclear phylogenetic genetic comparisons have been made. We used previously-published genotype data for 8 microsatellite DNA loci from 930 brown bears in 19 populations and 473 polar bears in 16 populations to compare the population genetic relationships of extant populations of the species. Genetic distances (Nei standard distance = 1.157), the proportion of private alleles (52% of alleles are not shared by the species), and Bayesian cluster analysis are consistent with morphological and life history characteristics that distinguish polar bears and brown bears as different species with little or no gene flow among extant populations.

北极熊（Ursus maritimus）与棕熊（Ursus arctos）是亲缘关系极近的物种，二者已被开展过广泛的线粒体及核基因组系统发育遗传学比较研究。本研究利用已发表的基因型数据，涵盖19个种群共930头棕熊、16个种群共473头北极熊的8个微卫星DNA位点信息，以比较该类群现存种群的群体遗传学关系。遗传距离（Nei标准遗传距离=1.157）、私有等位基因占比（两类物种共有等位基因比例为48%，即52%的等位基因为各自特有）以及贝叶斯聚类分析结果，均与形态学及生活史特征相符，支持北极熊与棕熊为不同物种，且现存种群间几乎无基因交流或基因交流极微弱。