Data from: Rapid, pervasive genetic differentiation of urban white-footed mouse (Peromyscus leucopus) populations in New York City

We investigated genetic diversity and structure of urban white-footed mouse, Peromyscus leucopus, populations in New York City (NYC) using variation at 18 microsatellite loci. White-footed mice are "urban adapters" that occur at higher population densities as habitat fragments are reduced in area, but have a limited ability to disperse through urbanized areas. We hypothesized that this combination of traits has produced substantial genetic structure but minimal loss of genetic variation over the last century in NYC. Allelic diversity and heterozygosity in fourteen NYC populations were high, and nearly all of our NYC study sites contained genetically distinct populations of white-footed mice as measured by pairwise FST, assignment tests, and Bayesian clustering analyses performed by Structure and BAPS. Analysis of molecular variance revealed that genetic differences between populations separated by a few km are more significant than differences between prehistorically isolated landmasses (i.e. Bronx, Queens, and Manhattan). Allele size permutation tests and lack of isolation-by-distance indicated that mutation and migration are less important than drift as explanations for structure in urban, fragmented P. leucopus populations. Peromyscus often exhibit little genetic structure over even regional scales, prompting us to conclude that urbanization is a particularly potent driver of genetic differentiation compared to natural fragmentation.

本研究利用18个微卫星位点（microsatellite loci）的遗传变异，对纽约市（NYC）市区内的白足鼠（Peromyscus leucopus）种群的遗传多样性与遗传结构展开了调查。白足鼠属于“城市适应性物种”：当栖息地片段面积缩减时，其种群密度会升高，但在城市化区域中的扩散能力十分有限。我们提出假说：这类性状的组合使得纽约市的白足鼠种群在过去一个世纪中形成了显著的遗传结构，但遗传变异并未出现明显丢失。本研究涉及的14个纽约市种群，其等位基因多样性与杂合度均处于较高水平；经两两FST遗传分化系数分析、个体归属测试以及由Structure与BAPS软件完成的贝叶斯聚类分析验证，几乎所有纽约市研究样地内的白足鼠种群均具有独特的遗传特征。分子方差分析结果表明，仅相隔数公里的种群间的遗传差异，比史前就相互隔离的陆块（即布朗克斯区、皇后区与曼哈顿区）之间的遗传差异更为显著。等位基因长度置换测试结果以及未呈现距离隔离（isolation-by-distance）模式的现象表明，相较于遗传漂变，突变与基因流在解释城市破碎化生境下的白足鼠种群遗传结构形成机制中作用更弱。鹿鼠属（Peromyscus）物种通常在区域尺度上几乎不存在明显的遗传结构，因此我们得出结论：与自然生境破碎化相比，城市化是驱动白足鼠种群遗传分化的尤为强力的因素。