Crotti Marco, Yohannes Elizabeth, Winfield Ian J, Lyle Alex A, Adams Colin E, Elmer Kathryn R
Institute of Biodiversity Animal Health & Comparative Medicine College of Medical, Veterinary & Life Sciences University of Glasgow Glasgow UK.
Limnological Institute University of Konstanz Konstanz Germany.
Evol Appl. 2021 Jul 6;14(10):2470-2489. doi: 10.1111/eva.13267. eCollection 2021 Oct.
Identifying the molecular mechanisms facilitating adaptation to new environments is a key question in evolutionary biology, especially in the face of current rapid and human-induced changes. Translocations have become an important tool for species conservation, but the attendant small population sizes and new ecological pressures might affect phenotypic and genotypic variation and trajectories dramatically and in unknown ways. In Scotland, the European whitefish () is native to only two lakes and vulnerable to extirpation. Six new refuge populations were established over the last 30 years as a conservation measure. In this study, we examined whether there is a predictable ecological and evolutionary response of these fishes to translocation. We found eco-morphological differences, as functional traits relating to body shape differed between source and refuge populations. Dual isotopic analyses suggested some ecological release, with the diets in refuge populations being more diverse than in source populations. Analyses of up to 9117 genome-mapped SNPs showed that refuge populations had reduced genetic diversity and elevated inbreeding and relatedness relative to source populations, though genomic differentiation was low ( = 0.002-0.030). We identified 14 genomic SNPs that showed shared signals of a selective response to translocations, including some located near or within genes involved in the immune system, nervous system and hepatic functions. Analysis of up to 120,897 epigenomic loci identified a component of consistent differential methylation between source and refuge populations. We found that epigenomic variation and genomic variation were associated with morphological variation, but we were not able to infer an effect of population age because the patterns were also linked with the methodology of the translocations. These results show that conservation-driven translocations affect evolutionary potential by impacting eco-morphological, genomic and epigenomic components of diversity, shedding light on acclimation and adaptation process in these contexts.
识别促进适应新环境的分子机制是进化生物学中的一个关键问题，尤其是在当前快速且由人类引发的变化面前。物种迁移已成为物种保护的一项重要工具，但随之而来的小种群规模和新的生态压力可能会以未知的方式显著影响表型和基因型变异及发展轨迹。在苏格兰，欧洲白鲑仅原产于两个湖泊，极易灭绝。在过去30年里，作为一项保护措施，建立了6个新的避难种群。在本研究中，我们调查了这些鱼类对迁移是否存在可预测的生态和进化反应。我们发现了生态形态差异，因为源种群和避难种群之间与体型相关的功能性状有所不同。双重同位素分析表明存在一定程度的生态释放，避难种群的饮食比源种群更加多样。对多达9117个基因组定位的单核苷酸多态性（SNP）的分析表明，相对于源种群，避难种群的遗传多样性降低，近亲繁殖和亲缘关系增加，尽管基因组分化程度较低（FST = 0.002 - 0.030）。我们鉴定出14个基因组SNP，它们显示出对迁移的选择性反应的共同信号，包括一些位于参与免疫系统、神经系统和肝脏功能的基因附近或内部的SNP。对多达120,897个表观基因组位点的分析确定了源种群和避难种群之间一致的差异甲基化成分。我们发现表观基因组变异和基因组变异与形态变异相关，但由于这些模式也与迁移方法有关，所以我们无法推断种群年龄的影响。这些结果表明，保护驱动的迁移通过影响多样性的生态形态、基因组和表观基因组成分来影响进化潜力，为这些情况下的适应和驯化过程提供了线索。
