Evolution and origin of sympatric shallow-water morphotypes of Lake Trout, Salvelinus namaycush, in Canada's Great Bear Lake

Range expansion in north-temperate fishes subsequent to the retreat of the Wisconsinan glaciers has resulted in the rapid colonization of previously unexploited, heterogeneous habitats and, in many situations, secondary contact among conspecific lineages that were once previously isolated. Such ecological opportunity coupled with reduced competition likely promoted morphological and genetic differentiation within and among post-glacial fish populations. Discrete morphological forms existing in sympatry, for example, have now been described in many species, yet few studies have directly assessed the association between morphological and genetic variation. Morphotypes of Lake Trout, Salvelinus namaycush, are found in several large-lake systems including Great Bear Lake (GBL), Northwest Territories, Canada, where several shallow-water forms are known. Here, we assess microsatellite and mitochondrial DNA variation among four morphotypes of Lake Trout from the five distinct arms of GBL, and ...威斯康星冰川（Wisconsinan glaciers）退缩后，北温带鱼类的分布范围得以扩张，使其快速拓殖此前未被开发利用的异质生境；在多数情境下，曾彼此隔离的同物种种系之间也发生了二次接触。这类生态机遇与竞争减弱的共同作用，大概率推动了冰期后鱼类种群内部及种群间的形态与遗传分化。例如，诸多物种中已有同域共存的离散形态型被报道，但目前鲜有研究直接评估形态变异与遗传变异之间的关联。湖红点鲑（Lake Trout，*Salvelinus namaycush*）的形态型分布于多个大湖生态系统中，其中包括加拿大西北地区的大熊湖（Great Bear Lake, GBL），该湖中已发现多种浅水型湖红点鲑。本研究针对大熊湖五个独立湖湾中的四种湖红点鲑形态型，评估其微卫星（microsatellite）与线粒体DNA（mitochondrial DNA）的遗传变异情况，以及……