Data from: Investigating the effects of Pleistocene events on genetic divergence within Richardsonius balteatus, a widely distributed western North American minnow

Background: Biogeographers seek to understand the influences of global climate shifts and geologic changes to the landscape on the ecology and evolution of organisms. Across both longer and shorter timeframes, the western North American landscape has experienced dynamic transformations related to various geologic processes and climatic oscillations, including events as recently as the Last Glacial Maximum (LGM; ~20 Ka) that have impacted the evolution of the North American biota. Redside shiner is a cyprinid species that is widely distributed throughout western North America. The species’ native range includes several well-documented Pleistocene refugia. Here we use mitochondrial DNA sequence data to assess phylogeography, and to test two biogeographic hypotheses regarding post-glacial colonization by redside shiner: 1) Redside shiner entered the Bonneville Basin at the time of the Bonneville Flood (Late Pleistocene; 14.5 Ka), and 2) redside shiner colonized British Columbia post-glacially from a single refugium in the Upper Columbia River drainage.

Results: Genetic diversification in redside shiner began in the mid to late Pleistocene, but was not associated with LGM. Different clades of redside shiner were distributed in multiple glacial age refugia, and each clade retains a signature of population expansion, with clades having secondary contact in some areas.

Conclusions: Divergence times between redside shiner populations in the Bonneville Basin and the Upper Snake/Columbia River drainage precedes the Bonneville Flood, thus it is unlikely that redside shiner invaded the Bonneville Basin during this flooding event. All but one British Columbia population of redside shiner are associated with the Upper Columbia River drainage with the lone exception being a population near the coast, suggesting that the province as a whole was colonized from multiple refugia, but the inland British Columbia redside shiner populations are affiliated with a refugium in the Upper Columbia River drainage.

背景：生物地理学家（Biogeographers）旨在阐明全球气候变化与地表地质变化对生物生态学与演化的影响。北美西部景观在长短不同的时间尺度上，均经历了与各类地质过程及气候振荡相关的动态演变，包括晚近的末次冰盛期（Last Glacial Maximum，LGM；约20千年前）这类影响北美生物区系演化的事件。红侧鲦（Redside shiner）是广泛分布于北美西部的鲤科物种，其原生分布区包含多处已被充分记录的更新世避难所。本研究利用线粒体DNA（mitochondrial DNA）序列数据解析其系统地理学（phylogeography）格局，并检验关于红侧鲦冰后拓殖（post-glacial colonization）的两项生物地理学假说：1）红侧鲦于邦纳维尔洪水（Bonneville Flood）时期（晚更新世；14.5千年前）进入邦纳维尔盆地（Bonneville Basin）；2）红侧鲦从哥伦比亚河上游流域（Upper Columbia River drainage）的单一避难所完成不列颠哥伦比亚省（British Columbia）的冰后拓殖。结果：红侧鲦的遗传分化始于更新世中晚期，但与末次冰盛期并无关联。不同进化枝（clade）的红侧鲦分布于多个冰期避难所，且每个进化枝均保留了种群扩张的信号，部分区域存在进化枝的二次接触现象。结论：邦纳维尔盆地与斯内克河上游/哥伦比亚河流域（Upper Snake/Columbia River drainage）的红侧鲦种群间的分化时间早于邦纳维尔洪水事件，因此红侧鲦不太可能在此次洪水事件中入侵邦纳维尔盆地。除沿海附近的1个种群外，不列颠哥伦比亚省其余所有红侧鲦种群均与哥伦比亚河上游流域相关联，这表明该省整体上由多个避难所完成拓殖，但内陆的不列颠哥伦比亚省红侧鲦种群隶属于哥伦比亚河上游流域的避难所。