Département de Biologie, Université Laval, Québec, QC, Canada.
Natural Sciences and Engineering Research Council of Canada (NSERC) Research Chair in Integrated Management of the Resources of Anticosti Island and Centre d'Études Nordiques (CEN), Québec, QC, Canada.
Mol Ecol. 2020 Jan;29(1):86-104. doi: 10.1111/mec.15317. Epub 2019 Dec 20.
Islands are generally colonized by few individuals which could lead to a founder effect causing loss of genetic diversity and rapid divergence by strong genetic drift. Insular conditions can also induce new selective pressures on populations. Here, we investigated the extent of genetic differentiation within a white-tailed deer (Odocoileus virginianus) population introduced on an island and its differentiation with its source mainland population. In response to their novel environmental conditions, introduced deer changed phenotypically from mainland individuals, therefore we investigated the genetic bases of the morphological differentiation. The study was conducted on Anticosti Island (Québec, Canada) where 220 individuals were introduced 120 years ago, resulting in a population size over 160,000 individuals. We used genotyping-by-sequencing (GBS) to generate 8,518 filtered high-quality SNPs and compared patterns of genetic diversity and differentiation between the continental and Anticosti Island populations. Clustering analyses indicated a single panmictic island population and no sign of isolation by distance. Our results revealed a weak, albeit highly significant, genetic differentiation between the Anticosti Island population and its source population (mean F = 0.005), which allowed a population assignment success of 93%. Also, the high genetic diversity maintained in the introduced population supports the absence of a strong founder effect due to the large number of founders followed by rapid population growth. We further used a polygenic approach to assess the genetic bases of the divergent phenotypical traits between insular and continental populations. We found loci related to muscular function and lipid metabolism, which suggested that these could be involved in local adaptation on Anticosti Island. We discuss these results in a harvest management context.
岛屿通常由少数个体殖民，这可能导致奠基者效应，导致遗传多样性丧失和强烈的遗传漂变导致快速分化。岛屿条件也会对种群产生新的选择压力。在这里，我们调查了引入岛屿上白尾鹿（Odocoileus virginianus）种群内的遗传分化程度及其与源大陆种群的分化程度。为了适应新的环境条件，引入的鹿在表型上与大陆个体发生了分化，因此我们调查了形态分化的遗传基础。该研究在安蒂科斯蒂岛（加拿大魁北克）进行，120 年前引入了 220 只个体，导致种群数量超过 16 万只。我们使用测序（GBS）生成了 8518 个过滤的高质量 SNP，并比较了大陆和安蒂科斯蒂岛种群的遗传多样性和分化模式。聚类分析表明，该岛屿种群是单一的、混合的，没有距离隔离的迹象。我们的结果显示，安蒂科斯蒂岛种群与其源种群之间存在微弱但高度显著的遗传分化（平均 F 为 0.005），这使得种群分配成功率达到了 93%。此外，引入种群中维持的高遗传多样性支持不存在强烈的奠基者效应，因为有大量的奠基者，随后种群快速增长。我们进一步使用多基因方法评估了岛屿和大陆种群之间分歧表型特征的遗传基础。我们发现了与肌肉功能和脂质代谢相关的基因座，这表明这些基因座可能参与了安蒂科斯蒂岛的局部适应。我们在收获管理背景下讨论了这些结果。
