Environmental and Life Sciences Graduate Program, Trent University, Ontario, Canada.
Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
Mol Biol Evol. 2023 Apr 4;40(4). doi: 10.1093/molbev/msad055.
Southeastern Canada is inhabited by an amalgam of hybridizing wolf-like canids, raising fundamental questions regarding their taxonomy, origins, and timing of hybridization events. Eastern wolves (Canis lycaon), specifically, have been the subject of significant controversy, being viewed as either a distinct taxonomic entity of conservation concern or a recent hybrid of coyotes (C. latrans) and grey wolves (C. lupus). Mitochondrial DNA analyses show some evidence of eastern wolves being North American evolved canids. In contrast, nuclear genome studies indicate eastern wolves are best described as a hybrid entity, but with unclear timing of hybridization events. To test hypotheses related to these competing findings we sequenced whole genomes of 25 individuals, representative of extant Canadian wolf-like canid types of known origin and levels of contemporary hybridization. Here we present data describing eastern wolves as a distinct taxonomic entity that evolved separately from grey wolves for the past ∼67,000 years with an admixture event with coyotes ∼37,000 years ago. We show that Great Lakes wolves originated as a product of admixture between grey wolves and eastern wolves after the last glaciation (∼8,000 years ago) while eastern coyotes originated as a product of admixture between "western" coyotes and eastern wolves during the last century. Eastern wolf nuclear genomes appear shaped by historical and contemporary gene flow with grey wolves and coyotes, yet evolutionary uniqueness remains among eastern wolves currently inhabiting a restricted range in southeastern Canada.
加拿大东南部地区生活着一群杂交狼-like 犬科动物，这引发了关于它们的分类学、起源和杂交事件时间的基本问题。特别是东部狼（Canis lycaon），一直是一个备受争议的话题，它们要么被视为一个独特的保护实体，要么被视为郊狼（C. latrans）和灰狼（C. lupus）的近期杂交种。线粒体 DNA 分析表明，东部狼是北美的进化犬科动物。相比之下，核基因组研究表明，东部狼最好被描述为一个杂交实体，但杂交事件的时间不清楚。为了检验与这些相互竞争的发现相关的假设，我们对 25 个个体的全基因组进行了测序，这些个体代表了已知起源和当代杂交水平的现存加拿大狼-like 犬科动物类型。在这里，我们提供的数据表明，东部狼是一个独特的分类实体，它与灰狼在过去约 67000 年前就已经分开进化，与郊狼的杂交事件发生在约 37000 年前。我们表明，大湖狼是灰狼和东部狼在末次冰期（约 8000 年前）后混合的产物，而东部郊狼则是“西部”郊狼和东部狼在上个世纪混合的产物。东部狼的核基因组似乎受到灰狼和郊狼的历史和当代基因流的影响，但目前居住在加拿大东南部有限范围内的东部狼仍然保持着进化上的独特性。
