Data from: The evolutionary origins of modularity

A central biological question is how natural organisms are so evolvable (capable of quickly adapting to new environments). A key driver of evolvability is the widespread modularity of biological networks--their organization as functional, sparsely connected subunits--but there is no consensus regarding why modularity itself evolved. While most hypotheses assume indirect selection for evolvability, here we demonstrate that the ubiquitous, direct selection pressure to reduce the cost of connections between network nodes causes the emergence of modular networks. Computational evolution experiments with selection pressures to maximize network performance and minimize connection costs yield networks that are significantly more modular and more evolvable than control experiments that only select for performance. These results will catalyze research in numerous disciplines, including neuroscience, genetics and harnessing evolution for engineering purposes.

核心生物学问题之一，在于自然生物为何具备如此强的演化能力——即能够快速适应全新环境。演化能力的关键驱动因素之一，是生物网络普遍存在的模块化特性：即其被组织为功能独立、连接稀疏的亚单元结构，但学界对于模块化本身为何会演化而来尚未达成共识。尽管多数假说均假定演化能力通过间接选择得以实现，但本研究证实，普遍存在的、旨在降低网络节点间连接成本的直接选择压力，会催生模块化网络结构。通过设置最大化网络性能、最小化连接成本的选择压力开展计算演化实验，所得网络相较于仅以性能为唯一选择目标的对照实验，其模块化程度与演化能力均显著更高。本研究结果将推动神经科学、遗传学以及利用演化进行工程设计等众多学科领域的研究发展。