Biological complexity is a key component of evolvability, yet its study has been hampered by a focus on evolutionary trends of complexification and inconsistent definitions. Here, we demonstrate the utility of bringing complexity into the framework of epigenetics to better investigate its utility as a concept in evolutionary biology. We first analyze the existing metrics of complexity and explore the link between complexity and adaptation. Although recently developed metrics allow for a unified framework, they omit developmental mechanisms. We argue that a better approach to the empirical study of complexity and its evolution includes developmental mechanisms. We then consider epigenetic mechanisms and their role in shaping developmental and evolutionary trajectories, as well as the development and organization of complexity. We argue that epigenetics itself could have emerged from complexity because of a need to self‐regulate. Finally, we explore hybridization complexes and hybrid organisms as potential models for studying the association between epigenetics and complexity. Our goal is not to explain trends in biological complexity but to help develop and elucidate novel questions in the investigation of biological complexity and its evolution.

中文翻译：

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在表观遗传学的框架下研究生物复杂性的演变和发展。

生物复杂性是可进化性的关键组成部分，然而，其研究一直由于关注复杂化的演化趋势和定义不一致而受到阻碍。在这里，我们演示了将复杂性纳入表观遗传学框架的效用，以更好地研究其作为进化生物学概念的效用。我们首先分析现有的复杂性指标，并探索复杂性和适应性之间的联系。尽管最近开发的指​​标允许使用统一的框架，但它们省略了开发机制。我们认为，对复杂性及其演变进行实证研究的更好方法包括发展机制。然后，我们考虑表观遗传机制及其在塑造发展和进化轨迹以及复杂性的发展和组织中的作用。我们认为表观遗传学本身可能是由于需要自我调节而从复杂性中产生的。最后，我们探索杂交复合物和杂交生物作为研究表观遗传学和复杂性之间关系的潜在模型。我们的目标不是解释生物复杂性的趋势，而是在研究生物复杂性及其演化时帮助发展和阐明新颖的问题。