Department of Zoology, University of Stockholm, 106 91 Stockholm, Sweden.
Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
Philos Trans R Soc Lond B Biol Sci. 2021 Jun 7;376(1826):20200121. doi: 10.1098/rstb.2020.0121. Epub 2021 Apr 19.
The cellular machinery that regulates gene expression can be self-propagated across cell division cycles and even generations. This renders gene expression states and their associated phenotypes heritable, independently of genetic changes. These phenotypic states, in turn, can be subject to selection and may influence evolutionary adaptation. In this review, we will discuss the molecular basis of epigenetic inheritance, the extent of its transmission and mechanisms of evolutionary adaptation. The current work shows that heritable gene expression can facilitate the process of adaptation through the increase of survival in a novel environment and by enlarging the size of beneficial mutational targets. Moreover, epigenetic control of gene expression enables stochastic switching between different phenotypes in populations that can potentially facilitate adaptation in rapidly fluctuating environments. Ecological studies of the variation of epigenetic markers (e.g. DNA methylation patterns) in wild populations show a potential contribution of this mode of inheritance to local adaptation in nature. However, the extent of the adaptive contribution of the naturally occurring variation in epi-alleles compared to genetic variation remains unclear. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'
调控基因表达的细胞机制可以在细胞分裂周期甚至世代之间自我传播。这使得基因表达状态及其相关表型具有遗传性，而与遗传变化无关。这些表型状态反过来又可以受到选择的影响，并可能影响进化适应。在这篇综述中，我们将讨论表观遗传遗传的分子基础、其传播的程度和进化适应的机制。目前的工作表明，可遗传的基因表达可以通过在新环境中提高生存率和扩大有益突变靶标来促进适应过程。此外，基因表达的表观遗传控制可以使不同表型在种群中随机转换，这可能有助于在快速波动的环境中适应。对野生种群中表观遗传标记（如 DNA 甲基化模式）变化的生态研究表明，这种遗传方式可能对自然环境中的局部适应有贡献。然而，与遗传变异相比，天然存在的 epi-alleles 变异的适应性贡献程度尚不清楚。本文是“表观遗传学如何影响进化过程？”这一主题问题的一部分。
