All humans age, but how we age—and how fast—differs considerably from person to person. This deviation between apparent age and chronological age is often referred to as “biological age” (BA) and until recently robust tools for studying BA have been scarce. “Epigenetic clocks” are starting to change this. Epigenetic clocks use predictable changes in the epigenome, usually DNA methylation, to estimate chronological age with unprecedented accuracy. More importantly, deviations between epigenetic age and chronological age predict a broad range of health outcomes and mortality risks better than chronological age alone. Thus, epigenetic clocks appear to capture fundamental molecular processes tied to BA and can serve as powerful tools for studying health, development, and aging across the lifespan. In this article, I review epigenetic clocks, especially as they relate to key theoretical and applied issues in human biology. I first provide an overview of how epigenetic clocks are constructed and what we know about them. I then discuss emerging applications of particular relevance to human biologists—those related to reproduction, life‐history, stress, and the environment. I conclude with an overview of the methods necessary for implementing epigenetic clocks, including considerations of study design, sample collection, and technical considerations for processing and interpreting epigenetic clocks. The goal of this review is to highlight some of the ways that epigenetic clocks can inform questions in human biology, and vice versa, and to provide human biologists with the foundational knowledge necessary to successfully incorporate epigenetic clocks into their research.

中文翻译：

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“表观遗传时钟”：人类生物学的理论与应用。

所有人都会变老，但我们变老的方式——以及变老的速度——因人而异。表观年龄和实足年龄之间的这种偏差通​​常被称为“生物年龄”（BA），直到最近，研究 BA 的强大工具一直很少。“表观遗传时钟”开始改变这一点。表观遗传时钟使用表观基因组中可预测的变化，通常是 DNA 甲基化，以前所未有的准确度估计实足年龄。更重要的是，表观遗传年龄和实足年龄之间的偏差比单独的实足年龄更能预测广泛的健康结果和死亡风险。因此，表观遗传时钟似乎捕获了与 BA 相关的基本分子过程，并且可以作为研究整个生命周期的健康、发育和衰老的有力工具。在这篇文章中，我回顾了表观遗传时钟，特别是因为它们与人类生物学中的关键理论和应用问题有关。我首先概述了表观遗传时钟的构建方式以及我们对它们的了解。然后我会讨论与人类生物学家特别相关的新兴应用——那些与繁殖、生活史、压力和环境有关的应用。最后，我概述了实施表观遗传时钟所需的方法，包括研究设计、样本收集以及处理和解释表观遗传时钟的技术考虑因素。本综述的目的是强调表观遗传时钟可以为人类生物学问题提供信息的一些方式，反之亦然，并为人类生物学家提供成功将表观遗传时钟纳入其研究所需的基础知识。