Stress is a common, if often unpredictable life event. It can be defined from an evolutionary perspective as a force an organism perceives it must adapt to. Thus stress is a useful tool to study adaptation and the adaptive capacity of organisms. The deep genome, long neglected as a pile of "junk" has emerged as a source of regulatory DNA and RNA as well as a potential stockpile of adaptive capacity at the organismal and species levels. Recent work on the regulation of transposable elements (TEs), the principle constituents of the deep genome, by stress has shown that these elements are responsive to host stress and other environmental cues. Further, we have shown that some are likely directly regulated by the glucocorticoid receptor (GR), one of the two major vertebrate stress steroid receptors in a fashion that appears adaptive. On the basis of this and other emerging evidence I argue that the deep genome may represent an adaptive toolkit for organisms to respond to their environments at both individual and evolutionary scales. This argues that genomes may be adapted for what Waddington called "trait adaptability" rather than being purely passive objects of natural selection and single nucleotide level mutation.

中文翻译：

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压力、适应和深层基因组：为什么转座子很重要

压力是一种常见的，但通常是不可预测的生活事件。它可以从进化的角度定义为一种生物体认为它必须适应的力量。因此，压力是研究生物体适应和适应能力的有用工具。长期被视为一堆“垃圾”的深层基因组已成为调节 DNA 和 RNA 的来源，以及生物体和物种水平的潜在适应能力储备。最近关于通过压力调节转座元件 (TE)（深层基因组的主要成分）的工作表明，这些元件对宿主压力和其他环境线索有反应。此外，我们已经表明，有些可能直接受糖皮质激素受体 (GR) 的调节，糖皮质激素受体是两种主要的脊椎动物应激类固醇受体之一，其方式似乎具有适应性。基于这一证据和其他新出现的证据，我认为深层基因组可能代表了生物体在个体和进化尺度上对环境做出反应的适应性工具包。这认为基因组可能适合 Waddington 所说的“性状适应性”，而不是纯粹被动的自然选择和单核苷酸水平突变的对象。