Luiken Jon M, Gamble Tony, Berendzen Peter B
Department of Biology University of Northern Iowa Cedar Falls Iowa USA.
Department of Biological Sciences Marquette University Milwaukee Wisconsin USA.
Ecol Evol. 2021 Dec 1;11(24):18305-18318. doi: 10.1002/ece3.8422. eCollection 2021 Dec.
Periodic glaciation during the Quaternary period shaped the contemporary riverscape and distribution of freshwater fishes in the Mississippi River drainage of central North America. The rainbow darter () is a member of this ichthyofauna and has a disjunct distribution in glaciated and unglaciated environments west of the Mississippi River. Based on glacial history of the region, there are different expectations on the observed spatial genetic structure of populations in these environments. The aim of this study was to utilize genome-wide SNP data to compare the population genomic structure of the rainbow darter in river networks with disparate glacial histories; the Volga River in the glaciated upper Mississippi River basin and the Meramec River in the unglaciated Ozark Plateau. Individuals were sampled from localities within each river system at distances dictated by the organismal life history and habitat preferences. Riverscape analyses were performed on three datasets: total combined localities of both rivers and one for each river independently. The results revealed a lasting influence of historic glaciation on the population genomic structure of rainbow darter populations. There was evidence of population expansion into the glaciated northern region following glacial retreat. The population genetic signature within the Volga River did not fit expectations of the stream hierarchy model, but revealed a pattern of repeated colonization and extirpation due to cyclic glaciation. The population within the unglaciated Meramec River adhered to the stream hierarchy model, with a directional order of genetic diversity based on the life history and habitat preferences of the species. These results demonstrate the importance of considering the geologic and climatic history of a region as well as the life history of an organism when interpreting spatial genetic patterns.
第四纪期间的周期性冰川作用塑造了北美中部密西西比河流域的当代河流水系景观以及淡水鱼类的分布。虹镖鲈（）是这一鱼类区系的成员，在密西西比河以西的冰川作用区和非冰川作用区呈间断分布。基于该地区的冰川历史，对于这些环境中观察到的种群空间遗传结构有不同的预期。本研究的目的是利用全基因组单核苷酸多态性（SNP）数据，比较冰川历史不同的河网中虹镖鲈的种群基因组结构；冰川作用的密西西比河上游流域的沃尔加河和非冰川作用的奥扎克高原的梅拉梅克河。根据生物的生活史和栖息地偏好确定的距离，从每个河流系统内的地点采集个体。对三个数据集进行了河流水系景观分析：两条河流的所有地点合并在一起，以及每条河流单独的一个数据集。结果揭示了历史冰川作用对虹镖鲈种群基因组结构的持久影响。有证据表明，冰川消退后种群向冰川作用的北部地区扩张。沃尔加河内的种群遗传特征不符合河流等级模型的预期，但揭示了由于周期性冰川作用导致的反复定殖和灭绝模式。非冰川作用的梅拉梅克河内的种群符合河流等级模型，根据物种的生活史和栖息地偏好呈现出遗传多样性的定向顺序。这些结果表明，在解释空间遗传模式时，考虑一个地区的地质和气候历史以及生物的生活史非常重要。
