Arctic marine ecosystems are undergoing rapid biogeographic responses to climate changes following the highest warming rates observed around the globe in recent decades. These drastic changes undoubtfully affect gene flow and genetic structure in the polar and subpolar regions. Here, we examine the genetic structure of the cold-water holozooplankton hyperiid Themisto libellula (Amphipoda: Hyperiidae), a key species in the Arctic ecosystem, using molecular population genetic approach. For the first time, we examine and compare populations across the Arcto-Pacific sector of the species biographical range from the northern Gulf of Alaska through the northern Chukchi Sea. We hypothesized that the complex history of the North Pacific and Amerasian Arctic marked by periodic intermissions and restrictions of the dominant northward flow resulted in vicariant differentiation of T. libellula along the latitudinal gradient. Mitochondrial and Rad-sequencing analyses revealed little genetic differentiation between closely connected Arctic populations in the Arctic Chukchi and Bering seas. In contrast, population from sub-Arctic glacial fjords in the Gulf of Alaska were distinct with few shared COI haplotypes. Strong FST estimates (FST = 0.16) based on 5197 neutral SNPs between the Gulf of Alaska and Bering Sea populations indicated very limited exchanges despite an existing connection between the areas via the Alaska Coastal Current. Our results suggest strong opportunities for genetic differentiation among marine zooplankton populations along the Pacific Alaskan coast and from the Arctic marginal seas.

中文翻译：

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来自阿拉斯加湾沿岸、白令海和楚科奇海的 Themisto libellula（端足目：Hyperiidae）的空间遗传结构

在近几十年来全球观测到的最高变暖率之后，北极海洋生态系统正在对气候变化进行快速的生物地理响应。这些剧烈的变化无疑会影响极地和亚极地的基因流动和基因结构。在这里，我们使用分子种群遗传方法检查了冷水全浮游动物 hyperiid Themisto libellula（端足类：Hyperiidae）的遗传结构，这是北极生态系统中的一个关键物种。我们第一次检查和比较了从阿拉斯加湾北部到楚科奇海北部的物种传记范围的北太平洋地区的种群。我们假设北太平洋和美亚北极地区的复杂历史以周期性间歇和主要向北流动的限制为标志，导致 T. libellula 沿纬度梯度发生替代分化。线粒体和 Rad 测序分析显示，北极楚科奇海和白令海中密切相关的北极种群之间几乎没有遗传差异。相比之下，来自阿拉斯加湾亚北极冰川峡湾的种群则截然不同，几乎没有共享的 COI 单倍型。基于阿拉斯加湾和白令海种群之间 5197 个中性 SNP 的强 FST 估计值 (FST = 0.16) 表明，尽管这些地区之间存在通过阿拉斯加沿岸流的联系，但交换非常有限。