Nov., 6, 2018// Understanding epigenetics through the lens of evolution

Dr. Adam Bewick, Department of Genetics, University of Georgia
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Heritable, genetic changes that contribute to phenotypic differences are the foundations of the Modern Synthesis. However, epigenetics, the molecular mechanism of heritable gene expression changes that cannot be attributed to changes in DNA sequence, potentially offers an alternative path for evolution. Despite what we know about the association of epigenomic variation to phenotypic variation, we lack a framework for understanding epigenetics in the context of the Modern Synthesis. An ongoing question is can epigenetics have a role in adaptive evolution through natural selection? If so, then do we see evidence of potentially adaptive epigenomic variation between and within species? Through phylogenetic comparative methods and functional genetics in plants, I have found substantial epigenomic variation between species. Contributors to epigenome divergence between plant species include lineage-specific genetic innovations that establish and maintain the epigenome. This variation is echoed at the population level, is heritable, and contributes to phenotypic differences among individuals, possibly meeting the requirements of natural selection. Thus, future work aims to identify adaptive epigenomic variation and its phenotypic consequences in plant populations by applying established population genetic theory to an epigenetic context. Extensions of this work include applied epigenetics for agricultural improvement. Ultimately, describing the role of epigenetics in evolution will require placing our knowledge in the context of the Modern Synthesis.