Rellstab Christian, Zoller Stefan, Walthert Lorenz, Lesur Isabelle, Pluess Andrea R, Graf René, Bodénès Catherine, Sperisen Christoph, Kremer Antoine, Gugerli Felix
WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland.
Genetic Diversity Centre, ETH Zürich, Universitätstrasse 16, 8092, Zürich, Switzerland.
Mol Ecol. 2016 Dec;25(23):5907-5924. doi: 10.1111/mec.13889. Epub 2016 Nov 7.
Testing how populations are locally adapted and predicting their response to their future environment is of key importance in view of climate change. Landscape genomics is a powerful approach to investigate genes and environmental factors involved in local adaptation. In a pooled amplicon sequencing approach of 94 genes in 71 populations, we tested whether >3500 single nucleotide polymorphisms (SNPs) in the three most common oak species in Switzerland (Quercus petraea, Q. pubescens, Q. robur) show an association with abiotic factors related to local topography, historical climate and soil characteristics. In the analysis including all species, the most frequently associated environmental factors were those best describing the habitats of the species. In the species-specific analyses, the most important environmental factors and associated SNPs greatly differed among species. However, we identified one SNP and seven genes that were associated with the same environmental factor across all species. We finally used regressions of allele frequencies of the most strongly associated SNPs along environmental gradients to predict the risk of nonadaptedness (RONA), which represents the average change in allele frequency at climate-associated loci theoretically required to match future climatic conditions. RONA is considerable for some populations and species (up to 48% in single populations) and strongly differs among species. Given the long generation time of oaks, some of the required allele frequency changes might not be realistic to achieve based on standing genetic variation. Hence, future adaptedness requires gene flow or planting of individuals carrying beneficial alleles from habitats currently matching future climatic conditions.
鉴于气候变化,测试种群如何在当地适应并预测它们对未来环境的反应至关重要。景观基因组学是研究参与局部适应的基因和环境因素的一种强大方法。在对瑞士71个种群中94个基因的混合扩增子测序方法中,我们测试了瑞士三种最常见的橡树物种(欧洲栓皮栎、柔毛栎、欧洲栎)中超过3500个单核苷酸多态性(SNP)是否与当地地形、历史气候和土壤特征相关的非生物因素存在关联。在包括所有物种的分析中,最常相关的环境因素是那些最能描述物种栖息地的因素。在物种特异性分析中,最重要的环境因素和相关的SNP在物种之间有很大差异。然而,我们确定了一个SNP和七个基因在所有物种中都与相同的环境因素相关。我们最终使用沿着环境梯度的最强烈相关SNP的等位基因频率回归来预测非适应性风险(RONA),它代表了理论上为匹配未来气候条件在与气候相关位点上所需的等位基因频率的平均变化。对于一些种群和物种来说,RONA相当可观(单个种群中高达48%),并且在物种之间有很大差异。鉴于橡树的世代时间很长,基于现有的遗传变异,一些所需的等位基因频率变化可能无法实现。因此,未来的适应性需要基因流动或种植携带来自目前与未来气候条件相匹配的栖息地的有益等位基因的个体。