Das Projekt "EpiCOL: Ecological and Evolutionary plant epigenetics (09-EuroEEFG-FP-048)" wird vom Umweltbundesamt gefördert und von Universität Bern, Departement Biologie, Institut für Pflanzenwissenschaften durchgeführt. One of the fundamental principles in biology is that evolution by natural selection, and therefore the ability of populations to adapt to changing environments, requires heritable variation, i.e. genetically-based variation in phenotypic traits that are under selection. Until recently, such heritable variation was generally thought to require underlying DNA sequence variation. Thus, populations that lack DNA sequence variation were assumed be unable to evolve. However, there is now increasing evidence that epigenetic modifications of the genome, such as DNA methylation or histone modifications - which regulate gene activity and therefore ultimately the phenotype - can be heritable, too, and that there can be epigenetic variation within and among natural populations which is independent of DNA sequence variation. Moreover, epigenetic variation can sometimes be altered direct by the environment, which suggests that such heritable epigenetic variation might be an important and hitherto overlooked component of biodiversity and an additional mechanism for organisms to respond to environmental change. Our project is part of a larger pan-European project (involving partners from the Netherlands, Germany, Austria and France) that attempts to address these exciting questions about the ecological and evolutionary relevance of epigenetic variation and epigenetic inheritance in several connected sub-projects. In our project, we will test the hypothesis that evolution by natural selection can occur even in the absence of DNA sequence variation, based on heritable epigenetic variation only. We will use selection experiments, and a recently developed, unique set of genotypically near-identical but epigenetically distinct recombinant inbred lines (epiRILs) of Arabidopsis thaliana to study epigenetic evolution 'in action'. The specific objectives of our project are (i) to characterise 100+ epiRILs with regard to their drought and pathogen resistance, (ii) to subject replicated experimental populations of these epiRILs to at least 3-4 generations of natural or artificial selection imposed by experimental drought and/or pathogens, and (iii) to quantify the response to this selection both in terms of phenotypic shifts as well as shifts in epigenotype frequencies.