Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
Mol Biol Evol. 2024 Sep 3;41(9). doi: 10.1093/molbev/msae170.
Epigenetics research in evolutionary biology encompasses a variety of research areas, from regulation of gene expression to inheritance of environmentally mediated phenotypes. Such divergent research foci can occasionally render the umbrella term "epigenetics" ambiguous. Here I discuss several areas of contemporary epigenetics research in the context of evolutionary biology, aiming to provide balanced views across timescales and molecular mechanisms. The importance of epigenetics in development is now being assessed in many nonmodel species. These studies not only confirm the importance of epigenetic marks in developmental processes, but also highlight the significant diversity in epigenetic regulatory mechanisms across taxa. Further, these comparative epigenomic studies have begun to show promise toward enhancing our understanding of how regulatory programs evolve. A key property of epigenetic marks is that they can be inherited along mitotic cell lineages, and epigenetic differences that occur during early development can have lasting consequences on the organismal phenotypes. Thus, epigenetic marks may play roles in short-term (within an organism's lifetime or to the next generation) adaptation and phenotypic plasticity. However, the extent to which observed epigenetic variation occurs independently of genetic influences remains uncertain, due to the widespread impact of genetics on epigenetic variation and the limited availability of comprehensive (epi)genomic resources from most species. While epigenetic marks can be inherited independently of genetic sequences in some species, there is little evidence that such "transgenerational inheritance" is a general phenomenon. Rather, molecular mechanisms of epigenetic inheritance are highly variable between species.
进化生物学中的表观遗传学研究涵盖了多个研究领域，从基因表达调控到环境介导表型的遗传。这种多样化的研究焦点有时会使“表观遗传学”这一总称变得模糊。在这里，我将在进化生物学的背景下讨论当代表观遗传学研究的几个领域，旨在提供跨越时间尺度和分子机制的平衡观点。表观遗传标记在发育中的重要性现在正在许多非模式物种中进行评估。这些研究不仅证实了表观遗传标记在发育过程中的重要性，而且还强调了跨分类群的表观遗传调控机制的显著多样性。此外，这些比较表观基因组学研究开始显示出增强我们对调控程序如何进化的理解的希望。表观遗传标记的一个关键特性是它们可以沿着有丝分裂细胞谱系遗传，并且早期发育过程中发生的表观遗传差异会对生物体的表型产生持久的影响。因此，表观遗传标记可能在短期（在生物体的生命周期内或到下一代）适应和表型可塑性中发挥作用。然而，由于遗传对表观遗传变异的广泛影响以及大多数物种中综合（表观）基因组资源的有限可用性，观察到的表观遗传变异在多大程度上独立于遗传影响仍然不确定。虽然在某些物种中，表观遗传标记可以独立于遗传序列遗传，但几乎没有证据表明这种“跨代遗传”是普遍现象。相反，表观遗传遗传的分子机制在物种之间高度可变。
