Epigenetics and its Implications for Plant Biology 2. The ‘Epigenetic Epiphany’: Epigenetics, Evolution and Beyond

Abstract

It is suggested that the ramifications of epigenetics in plant biology are immense, yet unappreciated. In contrast to the ease with which the DNA sequence can be studied, studying the complex patterns inherent in epigenetics poses many problems. Greater knowledge of patterns of epigenetic variation may be informative in taxonomy and systematics, as well as population biology and conservation.

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

“…Analyses of natural and induced epimutants have improved our understanding of epigenetics in ecological adaptation and evolutionary change [37][38][39][40]. In particular, experimental demethylation with DNMTi has contributed to reveal the broad range of plant traits and developmental processes that are regulated through DNA cytosine methylation, because such experiments have been able to, among others, alter sex expression [15], modify growth, leaf traits, flowering time or fruit ripening (e.g., [17,18,21,[41][42][43][44]), and induce dwarfism at maturity [14,17].…”

Transgenerational Epigenetic Inheritance: Prevalence, Mechanisms, and Implications for the Study of Heredity and Evolution

“…Conditions of stress seem to be particularly important as inducers of heritable epigenetic variation, and lead to changes in epigenetic and genetic organization that are targeted to specific genomic sequences. We mentioned earlier that the genomic stresses of allopolyploidization and, to a lesser extent, autopolyploidization lead to epigenetic and genetic re-patterning (Grant-Downton and Dickinson 2005Dickinson , 2006Rapp and Wendel 2005). A wellknown epigenetic phenomenon associated with hybridization is nucleolar dominance, or the expression in the hybrid of the rRNA gene complex (NOR) from only one parent.…”

Natural epigenetic variation in bats and its role in evolution

“…The epigenetic patterns, especially environmentinduced methylation variations from parents, may be erased and reset during the early development of the offspring. However, not all epigenetic marks are reset in each generation, and some of them may be stably inherited across generations as reported in many plant and animal species (Grant-Downton and Dickinson, 2006; Jablonka and Raz, 2009; Nätt et al, 2012;Richards, 2006). Heritable epigenetic variations that escape resetting provide the insight into the mechanisms of environmental adaption of bats.…”

“…Recent studies have suggested that epigenetic modifications in eukaryotes could affect genetic expression and thus may mediate phenotypical variation in response to rapid and unpredictable environmental changes without genetic divergence (Dolinoy et al, 2007;Gao et al, 2010; Kucharski et al, 2008). These environmentally induced epigenetic patterns may even be stably inherited by future generations (Grant-Downton and Dickinson, 2006; Jablonka and Lamb, 1998;Richards, 2006), which provides an additional pathway for environmental adaptation and produces a challenge to the Modern Evolutionary Synthesis (Bossdorf et al, 2008; Jablonka and Lamb, 1995; Jablonka et al, 2005), in that the epigenetic process is another source of random variation in natural populations in addition to genetic variance (Massicotte et al, 2011;Schmitz et al, 2011).DNA methylation, one of the key epigenetic markers, is a covalent modification that occurs at the fifth carbon position of a cytosine ring by DNA methyltransferases. DNA methylation can affect the transcription of genes by impeding the binding of transcriptional proteins to the gene or recruiting additional proteins to the locus in methyl-CpG binding domain protein forms.…”