The Role of Epigenetics in Evolution: The Extended Synthesis (original) (raw)
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Epigenetics and Evolution: An Overview
2010
After many years of neglect, the developmental aspect of heredity and its place in evolution are now receiving attention. In this overview, I discuss the relationship between epigenetic inheritance (mainly cellular epigenetic inheritance) and biological evolution. I point to six effects and implications of epigenetic inheritance that are important for evolutionary studies: (i) evolution can occur along the epigenetic axis without changes in DNA base sequence; (ii) epigenetic inheritance can affect the stability of the selective environment and speed up genetic accommodation; (iii) epigenetic variations can bias and target changes in DNA base sequence, leading to both microand macro-evolutionary changes; (iv) epigenetic inheritance constrains and channels the evolution of ontogeny; (v) epigenetic variations and epigenetic inheritance systems were important during the major evolutionary transitions; (vi) the genetic evolution of epigenetic inheritance systems is an important part of e...
Epigenetic Inheritance and Its Role in Evolutionary Biology: Re-Evaluation and New Perspectives
Biology, 2016
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.
The evolutionary implications of epigenetic inheritance
Interface Focus, 2017
The Modern Evolutionary Synthesis (MS) forged in the mid-twentieth century was built on a notion of heredity that excluded soft inheritance, the inheritance of the effects of developmental modifications. However, the discovery of molecular mechanisms that generate random and developmentally induced epigenetic variations is leading to a broadening of the notion of biological heredity that has consequences for ideas about evolution. After presenting some old challenges to the MS that were raised, among others, by Karl Popper, I discuss recent research on epigenetic inheritance, which provides experimental and theoretical support for these challenges. There is now good evidence that epigenetic inheritance is ubiquitous and is involved in adaptive evolution and macroevolution. I argue that the many evolutionary consequences of epigenetic inheritance open up new research areas and require the extension of the evolutionary synthesis beyond the current neo-Darwinian model.
Integrative and Comparative Biology, 2012
Epigenetics has become a topic with implications across a diversity of biological disciplines, inspiring exciting theoretical and empirical work. The term dates back to the work of Waddington in the 1940s who was one of the earliest researchers to disavow a simple relationship between genotype and phenotype. Since that time, interpretations of the term have evolved, particularly as molecular-level mechanisms that modulate gene expression have been revealed. Still, even since Waddington, the term has been used to refer to the ...
Epigenetic Inheritance and Evolution
1995
We discuss the role of cell memory in heredity and evolution. We describe the properties of the epigenetic inheritance systems (EISs) that underlie cell memory and enable environmentally and developmentally induced cell phenotypes to be transmitted in cell lineages, and argue that transgenerational epigenetic inheritance is an important and neglected part of heredity. By looking at the part EISs have played in the evolution of multicellularity, ontogeny, chromosome organization, and the origin of some post-mating isolating mechanisms, we show how considering the role of epigenetic inheritance can sometimes shed light on major evolutionary processes.
The Changing Concept of Epigenetics
Annals of the New York Academy of Sciences, 2006
We discuss the changing use of epigenetics, a term coined by Conrad Waddington in the 1940s, and how the epigenetic approach to development differs from the genetic approach. Originally, epigenetics referred to the study of the way genes and their products bring the phenotype into being. Today, it is primarily concerned with the mechanisms through which cells become committed to a particular form or function and through which that functional or structural state is then transmitted in cell lineages. We argue that modern epigenetics is important not only because it has practical significance for medicine, agriculture, and species conservation, but also because it has implications for the way in which we should view heredity and evolution. In particular, recognizing that there are epigenetic inheritance systems through which non-DNA variations can be transmitted in cell and organismal lineages broadens the concept of heredity and challenges the widely accepted gene-centered neo-Darwinian version of Darwinism.
The hairy problem of epigenetics in evolution
It has long been suspected that epigenetic mechanisms could contribute to heritable phenotypic variation, and thus to the diversity and evolutionary potential of natural populations. In recognition of the growing evidence bearing on this possibility, the National Evolutionary Synthesis Center (Durham, NC) recently hosted an interdisciplinary gathering of epigeneticists, experimental evolutionary ecologists, behavioral ecologists, theoretical population and quantitative geneticists and philosophers of science to discuss methods available to investigate epigenetic variation and epigenetic inheritance, as well as how to evaluate their importance for phenotypic evolution. This vibrant new arena is attracting empirical studies involving natural, non-model systems, including those merging robust ecological experimental design with chemical manipulation of genome-wide DNA methylation with 5-azacytidine or screening for methylation sensitive amplified fragment length polymorphisms (MS-AFLPs) in response to stress, different habitats and natural levels of herbivory. While these studies have convincingly shown correlations between genome wide changes in methylation with external environment, they ultimately are unsatisfying because surveys such as these do not readily translate into changes in expression of specific genes, particularly those that might be suspected to have ecological relevance. In general, across non-model systems with little or no DNA sequence information, it still is quite challenging to actually demonstrate the specific effects of epigenetic modification on ecologically and evolutionarily relevant phenotypes. Scoville et al. (2011) have taken a significant step forward in this direction,identifying a target gene that may be epigenetically modified, adding a remarkable new chapter to the emerging body of work on epigenetic inheritance of trichome density in yellow monkeyflower (Mimulus guttatus).
Epigenetic inheritance in evolution
Journal of Evolutionary Biology, 1998
We discuss the role of cell memory in heredity and evolution. We describe the properties of the epigenetic inheritance systems (EISs) that underlie cell memory and enable environmentally and developmentally induced cell phenotypes to be transmitted in cell lineages, and ...