Museum of Paleontology, University of Michigan, Ann Arbor, Michigan, USA.
The Natural History Museum, London, UK.
Evol Dev. 2021 Sep;23(5):377-403. doi: 10.1111/ede.12390. Epub 2021 Aug 31.
Modularity is now generally recognized as a fundamental feature of organisms, one that may have profound consequences for evolution. Modularity has recently become a major focus of research in organismal biology across multiple disciplines including genetics, developmental biology, functional morphology, population and evolutionary biology. While the wealth of new data, and also new theory, has provided exciting and novel insights, the concept of modularity has become increasingly ambiguous. That ambiguity is underlain by diverse intuitions about what modularity means, and the ambiguity is not merely about the meaning of the word-the metrics of modularity are measuring different properties and the methods for delimiting modules delimit them by different, sometimes conflicting criteria. The many definitions, metrics and methods can lead to substantial confusion not just about what modularity means as a word but also about what it means for evolution. Here we review various concepts, using graphical depictions of modules. We then review some of the metrics and methods for analyzing modularity at different levels. To place these in theoretical context, we briefly review theories about the origins and evolutionary consequences of modularity. Finally, we show how mismatches between concepts, metrics and methods can produce theoretical confusion, and how potentially illogical interpretations can be made sensible by a better match between definitions, metrics, and methods.
模块化现在被普遍认为是生物体的一个基本特征，它可能对进化产生深远的影响。模块化最近成为包括遗传学、发育生物学、功能形态学、种群和进化生物学在内的多个学科的研究重点。尽管大量的新数据和新理论提供了令人兴奋和新颖的见解，但模块化的概念变得越来越模糊。这种模糊性的基础是对模块化意味着什么的不同理解，而且这种模糊性不仅仅是关于这个词的含义——模块化的度量标准衡量的是不同的属性，而模块的划分方法则是通过不同的、有时甚至是相互冲突的标准来划分的。许多不同的定义、度量标准和方法不仅会导致对模块化作为一个词的含义的大量混淆，而且还会导致对其在进化中的含义的混淆。在这里，我们使用模块的图形表示来回顾各种概念。然后，我们回顾了一些用于在不同层次上分析模块化的度量标准和方法。为了将这些内容置于理论背景下，我们简要回顾了关于模块化起源和进化后果的理论。最后，我们展示了概念、度量标准和方法之间的不匹配如何导致理论上的混乱，以及通过更好地匹配定义、度量标准和方法，如何使潜在的不合逻辑的解释变得合理。
