Abstract
AbstractEpigenetic states offer an additional layer of variation besides genetic polymorphism that contribute to phenotypic variation and may arise either randomly or in response to environmental factors. We hypothesize that closely related species with different life-histories and habitat requirements could show distinct patterns of intraspecific epigenetic variation. We used Restriction-site Associated DNA sequencing (RADseq) and its bisulfite-converted variant (bsRADseq) to investigate in Sierra de Cazorla (SE Spain) the genetic and epigenetic population structure of two congeneric species, the endemic woody perennialErodium cazorlanumand the widely distributed annual herbE. cicutarium. Population genomics analyses revealed no structure in eitherE. cazorlanumandE. cicutarium,suggesting substantial gene flow between the study populations. In contrast, we found that the mean proportion of global DNA methylation was different between populations and species, withE. cazorlanumDNA showing higher methylation average and across-individuals variation. For each species, we searched for the loci with the strongest epigenetic differentiation between populations (differentially methylated cytosines, DMCs), and summarized them across regions (differentially methylated regions, DMRs). Multivariate analysis and hierarchical clustering of single cytosines’ methylation percentages did not group individuals by population, pointing to high epigenetic variation within populations. DMRs were enriched inCopiatransposable elements, putatively associated with stress response in plants. Our results suggest that variation at both genetic and epigenetic levels in our study area occur mainly within natural populations ofE. cazorlanumandE. cicutarium,with stronger population structure inE. cicutarium,and highlight the relevance of analyzing short distance spatial patterns.
Publisher
Cold Spring Harbor Laboratory