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.

核心生物学议题之一，在于自然生物何以具备如此优异的可演化性——即能够快速适配全新环境。可演化性的关键驱动因素之一，是生物网络普遍存在的模块化特性：生物网络以功能独立、连接稀疏的亚单元形式组织而成，但学界对于模块化本身的演化动因尚未达成共识。尽管多数假说均假定演化通过间接选择提升可演化性，但本研究证实，无处不在的、用于降低网络节点间连接成本的直接选择压力，会催生模块化网络的涌现。在以最大化网络性能、最小化连接成本为选择压力的计算演化实验中，所得网络相较于仅以性能为选择目标的对照实验，其模块化程度与可演化性均显著更高。本研究结果将推动神经科学、遗传学等众多学科的研究，并为利用演化开展工程应用的相关工作提供助力。