Role of gene body methylation in acclimatization and adaptation of a reef-building coral.

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The field of epigenetics studies modifications to DNA that do not change its sequence but do affect the function of the DNA. The study of epigenetics is a burgeoning and broadly popularized, with popular culture references outpacing the scientific data. What makes epigenetics so exciting is that it could be an entirely novel mechanism of altering gene function during evolution and adaptation. One type of epigenetic change is the addition of methyl groups to functional genes, termed ?gene body methylation?. Such changes are known to occur in diverse multicellular organisms, from sunflowers to humans, but thus far there was no direct evidence concerning its role in acclimatization or adaptation. The proposed project will fill this knowledge gap using a reef-building coral as a study system. Corals are primitive animals that can be clonally sampled by simple fragmentation, which allows researchers to disentangle the roles of genotype and environment. Also, corals recapitulate ancient features of animal genomes better than conventional model organisms. For example, both corals and humans possess gene body methylation while it is notably absent from the model fruit fly and the worm. The results of this project will therefore be broadly relevant for understanding fundamental mechanisms of molecular adaptation in multicellular animals. In addition, the project will generate much-needed insight into the capacity of reef-building corals to adapt to the rapidly changing climate, informing reef conservation and restoration approaches. Finally, the project will train multiple young scientists and disseminate methodologies and results through workshops to the public and broader scientific community.Gene body methylation (GBM) is a common DNA modification found throughout Metazoa, but its biological functions remains unclear. It has long been hypothesized that changes in epigenetic marks, including GBM, might modulate responses to environmental change and result in transgenerational plasticity, but thus far the evidence has been lacking. In this project, the function of GBM is addressed using reef-building corals as a study system. Corals are basal metazoans that can be clonally replicated and transplanted among environments, which makes them perfectly suited to disentangle effects of genotype and environment on any trait. The overarching hypothesis underlying the proposed research is that GBM is involved in long-term acclimatization, possibly spanning generations. The existing preliminary data indicate that GBM is indeed responsive to the environment and is linked to fitness of the transplanted individual. The experiments proposed here will include lab-based and field-based approaches and will investigate time scales of GBM modulation by the environment, its interaction with gene expression and fitness, and its heritability.This award was co-funded by the Division of Integrative Organismal Systems within The Directorate for Biological Sciences and the Division of Ocean Sciences within The Directorate for Geosciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.