Evolutionary Perspectives on Transgenerational Epigenetics

Transgenerational epigenetics is increasingly recognized in evolutionary biology. This chapter discusses the effects of germline or somatic epigenetic inheritance on phenotypic evolution. Both epigenetic inheritance that only spans two generations and more stable inheritance of epigenetic variants can cause evolutionary dynamics that deviate from those under pure genetic inheritance. Epigenetic inheritance can bring populations to different genetic and phenotypic equilibria and allow maintenance of polymorphisms. Of particular importance for predicting evolutionary trajectories is the stability of epigenetic variation and how its transmission dynamics are affected by the genetic, phenotypic, and environmental context. This implies that evolution of transgenerational epigenetic inheritance itself is important for phenotypic evolution. Models suggest that somatic epigenetic inheritance can be favored under a wide range of conditions. More or less stable transmission of epigenetic states through the germline, independently or together with soma-to-germ line inheritance, can also evolve in both temporally and spatially heterogeneous environments. These theoretical predictions provide a starting point for proof-of-principle experimental tests and evaluation of the adaptive significance of observed patterns of epigenetic stability in natural populations. © 2014 Elsevier Inc. All rights reserved.