CEFE – CNRS Montpellier, FRANCE
Gene DNA methylation in plants: selective pressures and sex chromosome evolution
Sex chromosome, methylation, epigenetic, transposable elements, mating system
A longstanding question is whether epigenetics can play a role in adaptation. We know that, in plants, some epigenetic marks can be transmitted over many generations and accumulate epimutations over time. If these heritable epigenetic marks can affect the fitness of individuals, they could potentially be the target of selection and allow species adaptation like genetic alleles. However, it is difficult to assess the effect of epigenetic marks on fitness due to linked genetic variation. We used a population epigenomics approach relying on the Site Frequency Spectrum (SFS) to infer the intensity of selection acting on DNA methylation in the 1001 methylome dataset of Arabidopsis thaliana. Our work suggests that some genes methylated in the CG context are under selection to remain CG methylated. This selection could be due to an effect of CG gene body methylation on gene expression level. Over the past years, the role of epigenetics in driving sex chromosome evolution has been revealed, mostly in animals. During the second part of my talk, I will present recent results illustrating the importance of DNA methylation in Y chromosome degeneration and sex chromosome evolution in the plant Silene latifolia.