Ecological genomics of anadromous migrations in a changing Arctic

鲑鱼是加拿大北部的主要水生物种，它们支撑着当地的经济发展和粮食安全。预测对迅速变化的北极可能的适应性反应是一个优先事项。溯河产卵（即淡水和咸水之间的迁移）是北方鲑科动物生态成功和经济重要性的关键特征，因为溯河产卵的个体更大，质量更高。但是，与咸水相比，气候变化增加了淡水的生产力，从而有利于非溯河产卵的个体。这可能对自给性渔业和新兴商业渔业造成破坏性影响。我们的工作将使用尖端的基因组工具来记录可能促进适应北极变化的遗传多样性的程度，并将描述两种具有经济重要性的北方鲑鱼溯河产卵迁移的遗传基础：北极红点鲑对北极变化的适应预测北极红点鲑是世界上分布最北的淡水鱼，是努纳武特和努纳维克捕捞量最大的鱼类。这一目标的工作将利用最近测序的北极红点鲑基因组，使用全基因组重测序方法来解决两个关键问题，预测物种对北极变化的反应。首先，我们将记录冰后期加拿大北极圈的影响范围基因组多样性。我们将模拟历史人口统计学，绘制出人类有利和有害等位基因的分布图。第二，我们将确定溯河产卵的迁移与样本的基因组基础从北极查尔人口溯河产卵和非溯河产卵的个人共存的同域性，从而显着有助于我们的能力，预测这种特性对气候变化的反应。 目标二：湖鳟鱼溯河产卵迁移湖鳟鱼通常被认为是一个淡水专业物种。然而，在两个北极地区，已经观察到溯河产卵的个体。这些种群提供了一个特殊的机会来了解像anadromy这样的复杂性状的遗传基础是如何保持的。首先，我们将使用声学遥测技术跟踪鳟鱼湖的海洋运动。然后，我们将使用RNAseq比较在野外捕获的溯河产卵和非溯河产卵个体，以表征与溯河产卵相关的遗传和功能差异。最后，我们将实验性地将来自淡水限制种群的湖鳟鱼暴露于水产养殖环境中的盐水中，并进行RNAseq以了解如何保持耐受盐水的能力。 我们的工作将大大有助于我们的能力，预测关键北方水产资源的快速变化的北极，并将培训4名研究生和至少3名本科生谁将获得不同的市场技能，在北极领域的生态学，生物信息学和基因组学。

Salmonids are dominant aquatic species in Canada's North and they underpin local economic development and food security. Predicting possible adaptive responses to a rapidly changing Arctic is a priority. Anadromy (i.e. migrations between fresh- and saltwater) is a key trait underlying the ecological success and the economic importance of northern salmonids because anadromous individuals are larger and higher-quality. But a changing climate increases the productivity of fresh- compared to saltwater, thus favoring non-anadromous individuals. This could have devastating impacts on subsistence and emerging commercial fisheries. Our work will use cutting-edge genomic tools to document extent genetic diversity likely to fuel adaptation to a changing Arctic, and will describe the genetic basis of anadromous migrations in two Northern salmonids of economic importance: Objective I: Predicting adaptation to a changing Arctic in Arctic Char Arctic Char are the freshwater fish with the northernmost distribution in the world and they are the most harvested fish in Nunavut and Nunavik. Work in this objective will leverage the recently sequenced Arctic Char genome to use a whole-genome resequencing approach to address two questions crucial to predicting the species response to a changing Arctic. First, we will document the impacts of post-glacial recolonization of the Canadian Arctic on extent genomic diversity. We will model historical demography and map the distribution of both putatively advantageous and deleterious alleles. Second, we will identify the genomic underpinnings of anadromous migrations with samples from Arctic Char populations where both anadromous and non-anadromous individuals co-exist in sympatry, thus significantly contributing to our ability to predict response of this trait to climate change. Objective II: Anadromous migrations in Lake Trout Lake Trout are generally regarded as a freshwater specialist species. In two Arctic locations, however, anadromous individuals have been observed. These populations offer an exceptional opportunity to understand how the genetic underpinnings of a complex trait like anadromy have been maintained. First, we will track the marine movements of Lake Trout using acoustic telemetry. We will then compare anadromous and non-anadromous individuals captured in the wild using RNAseq to characterize genetic and functional differences associated with anadromy. Finally, we will experimentally expose Lake Trout derived from freshwater-restricted populations to saltwater in an aquaculture setting and perform RNAseq to understand how the capacity to tolerate saltwater is maintained. Our work will contribute significantly to our ability to predict the response of key northern aquatic resources to a rapidly changing Arctic and will train 4 graduate and at least 3 undergraduate students who will acquire diverse marketable skills in Arctic field ecology, bioinformatics, and genomics.