Self-organization is a prerequisite of biological complexity. At the population level, it amounts to spontaneously sorting different individuals through space and time. Here, we reveal a simple mechanism by which different populations of motile cells can self-organize through a reciprocal control of their motilities. We first show how the reciprocal activation of motility between two populations of engineered Escherichia coli makes an initially mixed population of cells segregate, leading to out-of-phase population oscillations without the need of any preexisting positional or orientational cues. By redesigning the interaction, the original segregation between the two populations can be turned into co-localization. We account for this self-organization using a theoretical model that shows the reciprocal control of motility to be a robust and versatile self-organization pathway in multi-component systems. We finally show how our theoretical and experimental results can be generalized to three interacting bacterial populations.

自组织是生物学复杂性的前提。在人口层次上，它等于通过时空自发地对不同的个体进行分类。在这里，我们揭示了一种简单的机制，通过该机制，活动细胞的不同种群可以通过相互控制其活动性而自我组织。我们首先展示了两个工程化大肠杆菌种群之间的相互激活是如何运动的使最初混合的细胞群分离，从而导致异相的群振荡，而无需任何预先存在的位置或方向提示。通过重新设计交互作用，可以将两个种群之间的原始隔离变成共定位。我们使用一种理论模型来说明这种自我组织，该理论模型表明对运动的相互控制是多组件系统中强大且通用的自我组织路径。最后，我们展示了如何将我们的理论和实验结果推广到三个相互作用的细菌种群。