Population epigenomics of Swedish Arabidopsis

Plants display remarkable developmental and phenotypic plasticity in order to adapt to their environment. It has long been postulated that epigenetics plays a key role in these processes, but with one or two exceptions, solid evidence for the role of epigenetic variation in these processes is lacking. A key impediment to understanding these processes is the lack of information on the extent of epigenetic variation and how it relates to genetic and phenotypic variation in natural population, both over the lifecycle of an individual, and over evolutionary time. Here we show that genetic variants under selection in the north of Sweden appear to drive variation in DNA methylation, which in turn is highly correlated with local climate. Selective sweeps and genetic variants associated with adaptation to the local environment have previously been identified within the Swedish Arabidopsis population. Our finding that they harbour variants responsible for climate associated epigenetic variation strongly supports the role of epigenetic processes in local adaptation. These findings provide a basis for further dissecting the role of epigenetics in local adaptation at the molecular level Bisulfite sequencing of 113 F2 crosses between T550 and Brosarp-11-135.