Microbial range expansion experiments provide insight into the complex link between dynamic structure, pattern formation and evolutionary dynamics of growing populations. In this work, we develop a theoretical model in order to investigate the interplay of growth statistics and mechanical interactions which are implemented as division driven pushing and swapping of cells. For the case of the competitive growth of a strongly and a weakly interacting strain we investigate the influence of different mean division times, as well as different mechanical interactions on the development of the colony. Our results show that the susceptibility to cell division induced pushing has a much stronger influence on the structure of the colony than cell sorting towards the colony’s perimeter. Motivated by microbial range expansion experiments of Neisseria gonorrhoeae bacteria, we also consider the influence of mutating cells on the structure of the colony. We show that the outgrowth of the three different strains is strongly influenced by the relative strengths of their mechanical interaction. The experimentally observed patterns are reproduced for mechanical interactions of the mutants, which range between those of the strongly and weakly interacting strain.

微生物范围扩展实验提供了对不断增长的种群的动态结构、模式形成和进化动力学之间复杂联系的深入了解。在这项工作中，我们开发了一个理论模型，以研究生长统计数据和机械相互作用的相互作用，这些相互作用被实施为分裂驱动的细胞推动和交换。对于强相互作用和弱相互作用菌株的竞争性生长，我们研究了不同平均分裂时间以及不同机械相互作用对菌落发育的影响。我们的研究结果表明，对细胞分裂诱导推动的易感性对菌落结构的影响比细胞分选对菌落周边的影响要大得多。受微生物范围扩展实验的启发淋病奈瑟菌，我们还考虑了突变细胞对菌落结构的影响。我们表明，三种不同菌株的生长受到它们机械相互作用的相对强度的强烈影响。实验观察到的模式被复制用于突变体的机械相互作用，其范围在强相互作用菌株和弱相互作用菌株之间。