EVOLUTIONARY EPIGENETIC TEHORY by

Epigenetic effects are important in evolutionary biology. Yet, except in evolutionary developmental biology, there is little or no evolutionary epigenetic theory. Part of the problem has been not realizing how readily evolutionary epigenetics fits into existing formulations of quantitative and population genetics nor when it does not. Part of the problem has been delineating definitions of epigenetic signals and effects, i.e. reconciling developmental definitions with molecular definitions regarding cytosine methylation and chromatin formation. From a molecular perspective, epigenetic signals are heritable signals other than DNA nucleotides. From an ontogenetic perspective, epigenetic signals are those that affect development. To bridge this gap, I first develop several quantitative and population genetic models that include epigenetic effects and then develop applications that arise from these models. These model the relative fluidity of epigenetic signals and effects, and epigenetic changes induced by gene duplications. Altogether this dissertation presents nine key findings and conceptual advances. (1) Formal Fisherian models confirm that epigenetic effects can be considered equivalent to epistatic effects