Data from: Microsatellite genetic structure and cytonuclear discordance in naturally fragmented populations of deer mice (Peromyscus maniculatus)

The Great Lakes impose high levels of natural fragmentation on local populations of terrestrial animals in a way rarely found within continental ecosystems. Although separated by major water barriers, woodland deer mouse (Peromyscus maniculatus gracilis) populations on the islands and on the Upper Peninsula (UP) and Lower Peninsula (LP) of Michigan have previously been shown to have a mitochondrial DNA contact zone that is incongruent with the regional landscape. We analyzed 11 microsatellite loci for 16 populations of P. m. gracilis distributed across 2 peninsulas and 6 islands in northern Michigan to address the relative importance of geographical structure and inferred postglacial colonization patterns in determining the nuclear genetic structure of this species. Results showed relatively high levels of genetic structure for this species and a significant correlation between interpopulation differentiation and separation by water but little genetic structure and no isolation-by-distance within each of the 2 peninsulas. Genetic diversity was generally high on both peninsulas but lower and correlated to island size in the Beaver Island Archipelago. These results are consistent with the genetic and demographic isolation of Lower Peninsula populations, which is a matter of concern given the dramatic decline in P. m. gracilis abundance on the Lower Peninsula in recent years.

五大湖对当地陆生动物种群造成了高强度的自然生境破碎化，这种破碎模式在大陆生态系统中极为罕见。尽管被大型水体屏障分隔，密歇根州岛屿、上半岛（Upper Peninsula, UP）与下半岛（Lower Peninsula, LP）上的林地鹿鼠（*Peromyscus maniculatus gracilis*）种群此前已被证实存在与区域景观不一致的线粒体DNA（mitochondrial DNA）接触带。本研究针对分布于密歇根州北部2个半岛与6座岛屿的16个林地鹿鼠（*P. m. gracilis*）种群，分析了11个微卫星位点（microsatellite loci），旨在探究地理结构与推测的冰期后定殖模式在决定该物种核遗传结构中的相对重要性。研究结果显示，该物种整体呈现较高水平的遗传结构，且种群间遗传分化与水体分隔程度存在显著相关性；但在两个半岛内部，遗传结构极弱，且未检测到距离隔离效应。两个半岛的遗传多样性整体处于较高水平，但比弗岛群岛（Beaver Island Archipelago）内的种群遗传多样性更低，且与岛屿面积呈显著相关。上述结果与下半岛种群的遗传与种群统计隔离状态相符；鉴于近年来密歇根下半岛的林地鹿鼠种群数量大幅下降，该现状值得高度关注。