Epigenetic Inheritance and Its Role in Evolutionary Biology: Re-Evaluation and New Perspectives

Abstract

Epigenetics increasingly occupies a pivotal position in our understanding of inheritance, natural selection and, perhaps, even evolution. A survey of the PubMed database, however, reveals that the great majority (>93%) of epigenetic papers have an intra-, rather than an inter-generational focus, primarily on mechanisms and disease. Approximately ~1% of epigenetic papers even mention the nexus of epigenetics, natural selection and evolution. Yet, when environments are dynamic (e.g., climate change effects), there may be an “epigenetic advantage” to phenotypic switching by epigenetic inheritance, rather than by gene mutation. An epigenetically-inherited trait can arise simultaneously in many individuals, as opposed to a single individual with a gene mutation. Moreover, a transient epigenetically-modified phenotype can be quickly “sunsetted”, with individuals reverting to the original phenotype. Thus, epigenetic phenotype switching is dynamic and temporary and can help bridge periods of environmental stress. Epigenetic inheritance likely contributes to evolution both directly and indirectly. While there is as yet incomplete evidence of direct permanent incorporation of a complex epigenetic phenotype into the genome, doubtlessly, the presence of epigenetic markers and the phenotypes they create (which may sort quite separately from the genotype within a population) will influence natural selection and, so, drive the collective genotype of a population.

Evolutionary consequences of multidriver environmental change in an aquatic primary producer

“…This may be followed by compensatory mutations that increase fitness by reversing the effect of the initial mutation on traits where change was not adaptive (46)(47)(48). Second, heritable epigenetic mutations or transgenerational plasticity can contribute to early adaptation (7) but eventually be replaced by genetic mutations (49)(50)(51)(52). Understanding how trait reversion is linked to adaptation presents an opportunity to improve our predictions of functional trait values in primary producers in aquatic environments.…”

Tissue-Specific Response to Experimental Demethylation at Seed Germination in the Non-Model Herb Erodium cicutarium

“…These epigenetic changes are highly dynamic, are often under environmental or developmental influence, and their phenotypic consequences can be analyzed at cell, tissue, and organism levels [1][2][3][4]. In plants, epigenetic regulation has been related to individual and population responses to environmental stress and there is a growing interest in understanding how epigenetic regulation can contribute to transgenerational stress memories [5][6][7][8][9].…”

Recent advances in computational epigenetics

“…21,22 Epigenetic marks also reflect imprinting of genes by environmental factors such as diet and lifestyle, with such information also passed on to subsequent generations. [23][24][25][26] In recent years, heterogeneous micromolecular abnormalities have become increasingly associated with risk, onset and progression of a range of conditions and diseases, such as obesity, 11,27 mood disorders and other psychopathologies, [28][29][30] autoimmune and cardiovascular diseases, 31,32 as well as cancers 33 and ageing. [34][35][36] Moreover, the reversible nature and faster dynamics of epigenetic changes are of major interest in the targeting of intervention, providing key motivation for pharmaceutical development over the last decade.…”

“…26 High-level descriptions of biological processes and their concomitant entities are available from the literature and experimental studies, but quantitative data, mainly captured through molecular and epigenetic databases, are increasingly abundant. Such resources range from the small and specialized to extensions of well-established and wide-ranging repositories of nucleotide sequences, transcriptional regulatory sites and transcription factors for human genes and diseases, as well as microarray and gene expression data.…”