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Abstract：
The epigenome is the suite of interacting chemical marks and molecules that helps to shape patterns of development, phenotypic plasticity and gene regulation, in part due to its responsiveness to environmental stimuli. There is increasing interest in understanding the functional and evolutionary importance of this sensitivity under ecologically realistic conditions. Observations that epigenetic variation abounds in natural populations have prompted speculation that it may facilitate evolutionary responses to rapid environmental perturbations, such as those occurring under climate change. A frequent point of contention is whether epigenetic variants reflect genetic variation or are independent of it. The genome and epigenome often appear tightly linked and interdependent. While many epigenetic changes are genetically determined, the converse is also true, with DNA sequence changes influenced by the presence of epigenetic marks. Understanding how the epigenome, genome and environment interact with one another is therefore an essential step in explaining the broader evolutionary consequences of epigenomic variation. Drawing on results from experimental and comparative studies carried out in diverse plant and animal species, we synthesize our current understanding of how these factors interact to shape phenotypic variation in natural populations, with a focus on identifying similarities and differences between taxonomic groups. We describe the main components of the epigenome and how they vary within and between taxa. We review how variation in the epigenome interacts with genetic features and environmental determinants, with a focus on the role of transposable elements (TEs) in integrating the epigenome, genome and environment. And we look at recent studies investigating the functional and evolutionary consequences of these interactions. Although epigenetic differentiation in nature is likely often a result of drift or selection on stochastic epimutations, there is growing evidence that a significant fraction of it can be stably inherited and could therefore contribute to evolution independently of genetic change.
摘要：
表观基因组是一组相互作用的化学标记和分子，有助于塑造发育模式，表型可塑性和基因调控，部分原因是它对环境刺激的反应。在生态现实条件下，人们越来越有兴趣了解这种敏感性的功能和进化重要性。观察到自然种群中大量存在表观遗传变异，这促使人们猜测它可能促进对快速环境扰动的进化反应，比如在气候变化下发生的。一个常见的争论点是表观遗传变异是反映遗传变异还是独立于遗传变异。基因组和表观基因组通常表现为紧密相连和相互依赖。虽然许多表观遗传变化是由遗传决定的，反之亦然，DNA序列的变化受到表观遗传标记的影响。了解表观基因组，因此，基因组和环境相互作用是解释表观基因组变异更广泛的进化后果的重要步骤。借鉴在不同植物和动物物种中进行的实验和比较研究的结果，我们综合了我们目前对这些因素如何相互作用以形成自然种群中的表型变异的理解，重点是确定分类群体之间的异同。我们描述了表观基因组的主要组成部分，以及它们在分类单元内和分类单元之间的变化。我们回顾了表观基因组中的变异如何与遗传特征和环境决定因素相互作用，重点关注转座因子（TE）在整合表观基因组中的作用，基因组和环境。我们看看最近的研究，调查这些相互作用的功能和进化后果。尽管自然界中的表观遗传分化通常可能是随机表观突变的漂移或选择的结果，越来越多的证据表明，其中很大一部分可以稳定遗传，因此可以独立于遗传变化而促进进化。
