Data from: Genetic variation and structure in contrasting geographic distributions: widespread vs. restricted black-tailed prairie dogs (subgenus Cynomys)

Species of restricted distribution are considered more vulnerable to extinction because of low levels of genetic variation relative to widespread taxa. Species of the subgenus Cynomys are an excellent system to compare genetic variation and degree of genetic structure in contrasting geographic distributions. We assessed levels of genetic variation, genetic structure, and genetic differentiation in widespread Cynomys ludovicianus and restricted C. mexicanus using 1997bp from the cytochrome b and control region (n = 223 C. ludovicianus; 77 C. mexicanus), and 10 nuclear microsatellite loci (n = 207 and 78, respectively). Genetic variation for both species was high, and genetic structure in the widespread species was higher than in the restricted species. C. mexicanus showed values of genetic variation, genetic structure, and genetic differentiation similar to C. ludovicianus at smaller geographic scales. Results suggest the presence of at least 2 historical refuges for C. ludovicianus and that the Sierra Madre Occidental represents a barrier to gene flow. Chihuahua and New Mexico possess high levels of genetic diversity and should be protected, while Sonora should be treated as an independent management unit. For C. mexicanus, connectivity among colonies is very important and habitat fragmentation and habitat loss should be mitigated to maintain gene flow.

分布受限的物种因遗传变异水平低于广布类群，被认为更易面临灭绝威胁。犬鼠亚属（Cynomys）物种是对比不同地理分布格局下遗传变异与遗传结构程度的绝佳研究体系。本研究针对广布的路德维希草原犬鼠（Cynomys ludovicianus）与分布受限的墨西哥草原犬鼠（C. mexicanus），借助细胞色素b基因与控制区的1997bp序列（样本量分别为223份C. ludovicianus、77份C. mexicanus）以及10个核微卫星位点（对应样本量分别为207份与78份），评估了二者的遗传变异水平、遗传结构与遗传分化程度。两种物种的遗传变异水平均较高，且广布物种的遗传结构程度高于分布受限物种。墨西哥草原犬鼠在较小地理尺度下的遗传变异、遗传结构与遗传分化水平与路德维希草原犬鼠相近。研究结果表明，路德维希草原犬鼠至少存在2处历史避难所，且西马德雷山脉（Sierra Madre Occidental）构成了基因流的障碍。奇瓦瓦州与新墨西哥州拥有较高的遗传多样性，应予以保护；索诺拉州则应被视为独立的管理单元。对于墨西哥草原犬鼠而言，种群间的连通性至关重要，需通过缓解生境破碎化与生境丧失以维持基因流。