Insect–bacterial symbioses are ubiquitous, but there is still much to uncover about how these relationships establish, persist and evolve. The tsetse endosymbiont Sodalis glossinidius displays intriguing metabolic adaptations to its microenvironment, but the process by which this relationship evolved remains to be elucidated. The recent chance discovery of the free-living species of the genus Sodalis , Sodalis praecaptivus , provides a serendipitous starting point from which to investigate the evolution of this symbiosis. Here, we present a flux balance model for S. praecaptivus and empirically verify its predictions. Metabolic modelling is used in combination with a multi-objective evolutionary algorithm to explore the trajectories that S. glossinidius may have undertaken from this starting point after becoming internalized. The order in which key genes are lost is shown to influence the evolved populations, providing possible targets for future in vitro genetic manipulation. This method provides a detailed perspective on possible evolutionary trajectories for S. glossinidius in this fundamental process of evolutionary and ecological change.

中文翻译：

---

模拟 Sodalis 属昆虫共生体代谢途径的进化轨迹。


昆虫与细菌的共生关系无处不在，但关于这些关系如何建立、持续和进化，仍有很多东西有待揭示。采采蝇内共生体Sodalis Glossinidius显示出对其微环境的有趣的代谢适应，但这种关系进化的过程仍有待阐明。最近偶然发现的Sodalis属自由生活物种Sodalis praecaptivus为研究这种共生关系的进化提供了一个偶然的起点。在这里，我们提出了S. praecaptivus的通量平衡模型，并凭经验验证了其预测。代谢模型与多目标进化算法相结合，探索S. glosesinidius在内化后从这个起点可能采取的轨迹。关键基因丢失的顺序被证明会影响进化的种群，为未来的体外遗传操作提供可能的目标。该方法为S. glosesinidius在进化和生态变化的基本过程中可能的进化轨迹提供了详细的视角。