Ecological, genetic and evolutionary drivers of regional genetic differentiation in Arabidopsis thaliana

BMC Evolutionary Biology

article

Castilla, Antonio R.¹  Méndez-Vigo, Belén³  Marcer, Arnald⁴  Martínez-Minaya, Joaquín⁶  Conesa, David⁷  Picó, F. Xavier²  Alonso-Blanco, Carlos³ 

[1] Centre for Applied Ecology “Prof. Baeta Neves”, School of Agriculture, University of Lisbon;Departamento de Ecología Integrativa;Departamento de Genética Molecular de Plantas;Centre de Recerca Ecològica i Aplicacions Forestals;Universitat Autònoma de Barcelona;BCAM - Basque Center for Applied Mathematics;Universitat de València

关键词: Genetic diversity;    Genetic structure;    Iberian Peninsula;    Nested maximum-likelihood population effect models;    Precipitation seasonality;    Spatial hierarchical Bayesian models;   

DOI  :  10.1186/s12862-020-01635-2

学科分类：护理学

来源: BioMed Central

【 摘 要 】

Disentangling the drivers of genetic differentiation is one of the cornerstones in evolution. This is because genetic diversity, and the way in which it is partitioned within and among populations across space, is an important asset for the ability of populations to adapt and persist in changing environments. We tested three major hypotheses accounting for genetic differentiation—isolation-by-distance (IBD), isolation-by-environment (IBE) and isolation-by-resistance (IBR)—in the annual plant Arabidopsis thaliana across the Iberian Peninsula, the region with the largest genomic diversity. To that end, we sampled, genotyped with genome-wide SNPs, and analyzed 1772 individuals from 278 populations distributed across the Iberian Peninsula. IBD, and to a lesser extent IBE, were the most important drivers of genetic differentiation in A. thaliana. In other words, dispersal limitation, genetic drift, and to a lesser extent local adaptation to environmental gradients, accounted for the within- and among-population distribution of genetic diversity. Analyses applied to the four Iberian genetic clusters, which represent the joint outcome of the long demographic and adaptive history of the species in the region, showed similar results except for one cluster, in which IBR (a function of landscape heterogeneity) was the most important driver of genetic differentiation. Using spatial hierarchical Bayesian models, we found that precipitation seasonality and topsoil pH chiefly accounted for the geographic distribution of genetic diversity in Iberian A. thaliana. Overall, the interplay between the influence of precipitation seasonality on genetic diversity and the effect of restricted dispersal and genetic drift on genetic differentiation emerges as the major forces underlying the evolutionary trajectory of Iberian A. thaliana.

【 授权许可】

CC BY|CC0