Martin Claudia A, Armstrong Claire, Illera Juan Carlos, Emerson Brent C, Richardson David S, Spurgin Lewis G
School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, UK.
R Soc Open Sci. 2021 Feb 3;8(2):201146. doi: 10.1098/rsos.201146.
Oceanic island archipelagos provide excellent models to understand evolutionary processes. Colonization events and gene flow can interact with selection to shape genetic variation at different spatial scales. Landscape-scale variation in biotic and abiotic factors may drive fine-scale selection within islands, while long-term evolutionary processes may drive divergence between distantly related populations. Here, we examine patterns of population history and selection between recently diverged populations of the Berthelot's pipit (), a passerine endemic to three North Atlantic archipelagos. First, we use demographic trees and statistics to show that genome-wide divergence across the species range is largely shaped by colonization and bottlenecks, with evidence of very weak gene flow between populations. Then, using a genome scan approach, we identify signatures of divergent selection within archipelagos at single nucleotide polymorphisms (SNPs) in genes potentially associated with craniofacial development and DNA repair. We did not detect within-archipelago selection at the same SNPs as were detected previously at broader spatial scales between archipelagos, but did identify signatures of selection at loci associated with similar biological functions. These findings suggest that similar ecological factors may repeatedly drive selection between recently separated populations, as well as at broad spatial scales across varied landscapes.
大洋岛屿群岛为理解进化过程提供了绝佳模型。殖民事件和基因流可与选择相互作用，从而在不同空间尺度上塑造遗传变异。生物和非生物因素在景观尺度上的变化可能会驱动岛屿内部的精细尺度选择，而长期进化过程可能会导致远缘种群之间的分化。在这里，我们研究了贝氏鹨（一种分布于北大西洋三个群岛的雀形目鸟类）最近分化的种群之间的种群历史和选择模式。首先，我们使用种群动态树和统计方法表明，整个物种范围内的全基因组分化在很大程度上是由殖民和瓶颈效应塑造的，种群之间的基因流非常微弱。然后，我们采用全基因组扫描方法，在可能与颅面发育和DNA修复相关的基因中的单核苷酸多态性（SNP）位点上，识别出群岛内部趋异选择的特征。我们在群岛内部没有检测到与之前在群岛之间更广泛空间尺度上检测到的相同SNP位点的选择，但确实在与相似生物学功能相关的基因座上识别出了选择特征。这些发现表明，相似的生态因素可能会反复驱动最近分离的种群之间以及不同景观的广泛空间尺度上的选择。
