Condori Brian, Recuerda María, Illera Juan Carlos, Milá Borja
Department of Biodiversity and Evolutionary Biology National Museum of Natural Sciences, Spanish National Research Council (CSIC) Madrid Spain.
Cornell Laboratory of Ornithology Cornell University Ithaca New York USA.
Ecol Evol. 2025 Apr 15;15(4):e71307. doi: 10.1002/ece3.71307. eCollection 2025 Apr.
Island populations diverge from the mainland and from each other by both natural selection and neutral forces such as founder effects and genetic drift. In this work, we aim to determine the relative roles of selection and drift in the diversification of chaffinches ( spp.) in Macaronesia. We tested the hypothesis that taxa inhabiting Macaronesian archipelagos, which exhibit significant differences in habitat and climate compared with the mainland, should experience distinct ecological pressures, leading to divergence at loci under selection related to environmental variables. To determine the role of local adaptation in the differentiation of these taxa, we performed genotype-environment association (GEA) analyses using ten environmental variables and 52,306 single nucleotide polymorphism markers obtained from genotyping-by-sequencing (GBS) in 79 chaffinches. Redundancy analysis (RDA) revealed that genomic variation is associated with environmental variables and identified candidate genes related to phenotypic traits and environmental variables. Variables associated with habitat type and precipitation, together with drift, played an important role in the genomic differentiation between chaffinches from Macaronesia and the mainland, as well as within the Canarian archipelago. Genetic drift was identified as the main factor in the differentiation of North African chaffinches from Macaronesia and mainland Europe, as well as Madeira chaffinches from those in the Canary Islands. Finally, chaffinches from the Canary Islands show an incipient diversification process at the genetic and phenotypic level driven by both selection and neutral processes. Our results suggest that both habitat-driven local adaptation and drift have played a role in the radiation of chaffinch taxa in Macaronesia.
岛屿种群通过自然选择以及奠基者效应和遗传漂变等中性力量与大陆种群以及彼此之间产生分化。在这项研究中，我们旨在确定选择和漂变在马卡罗尼西亚苍头燕雀（ spp.）多样化过程中的相对作用。我们检验了这样一个假设：栖息在马卡罗尼西亚群岛的分类群，与大陆相比，其栖息地和气候存在显著差异，应该会经历独特的生态压力，从而导致在与环境变量相关的受选择基因座上出现分化。为了确定局部适应在这些分类群分化中的作用，我们使用十个环境变量和从79只苍头燕雀的简化基因组测序（GBS）中获得的52306个单核苷酸多态性标记进行了基因型 - 环境关联（GEA）分析。冗余分析（RDA）表明基因组变异与环境变量相关，并鉴定出与表型性状和环境变量相关的候选基因。与栖息地类型和降水量相关的变量，以及漂变，在马卡罗尼西亚苍头燕雀与大陆以及加那利群岛内部的基因组分化中发挥了重要作用。遗传漂变被确定为北非苍头燕雀与马卡罗尼西亚和欧洲大陆、以及马德拉岛苍头燕雀与加那利群岛苍头燕雀分化的主要因素。最后，加那利群岛的苍头燕雀在遗传和表型水平上表现出由选择和中性过程驱动的初步多样化过程。我们的结果表明，栖息地驱动的局部适应和漂变在马卡罗尼西亚苍头燕雀分类群的辐射中都发挥了作用。
