Epigenetic mechanisms such as DNA methylation, are affecting gene expression during early development. At the same time, they provide a plausible mechanism that translates environmental changes to phenotypic changes. If these induced environmental changes are maintained throughout the lifetime of an organism or are inherited transgenerationally, they have the potential to influence the expected evolutionary outcome of rapid environmental changes such as climate change and urbanization. Evidence for this hypothesis is largely lacking in vertebrates. Using the great tit (Parus major) as an ecological model organism, we here show that the roles of epigenetic variation are diverse. Where DNA methylation seems to play a major role in shaping a preprogrammed early life development, between-individual variation in methylation is largely explained by genetic variation. We repeatedly find low correlations of between-individual variation in methylation with environmentally induced phenotypic changes, providing limited scope for adaptive phenotypic changes via environmentally induced DNA methylation. Within-individual fluctuations in DNA methylation nonetheless rely on environmental input, suggesting that genetic variation related to this epigenetic variation is a strong candidate explaining the genetic underpinning We conclude that DNA methylation mostly represents a series of processes that orchestrate a dynamic change in gene expression under the control of genetic variation. of phenotypic plasticity. We here present results supporting this idea and discuss the implications.
|Publication status||Published - 17 Aug 2022|