Inheritance of epigenome variants across generations and its implications on the emergence of phenotypic novelties during evolution

Epigenetic modifications to chromatin are continuously "re-edited" based on environmental information. This process causes subsequent generations to inherit epigenomes that vary in differing degrees from those of their parents. Inheritance of epigenome variants across generations then, may lead to the emergence of phenotypic novelties and, ultimately, to speciation. The re-editing of epigenetic marks proceeds at rates that vary considerably, even amongst genetically identical individuals. This lack of stable heritability has led some researchers to downplay epigenetics' broader evolutionary significance. Nonetheless, the varying degrees of epigenome re-editing during development may lead to epiallelic variants - an array of epigenetic states for a single allele. Multiple epiallelic variants, then, may explain the widespread phenotypic variation observed in nature. This chapter discusses the inheritance of epigenetic modifications and how they may be important for generating phenotypic novelties.