CNRS, Institut de Biologie Paris-Seine, Laboratoire Jean Perrin (UMR 8237), Sorbonne Université, F-75005 Paris, France.
CNRS, Institut de Biologie Paris-Seine, Laboratoire Jean Perrin (UMR 8237), Sorbonne Université, F-75005 Paris, France;
Proc Natl Acad Sci U S A. 2022 Jan 4;119(1). doi: 10.1073/pnas.2108671119.
The gut microbiota features important genetic diversity, and the specific spatial features of the gut may shape evolution within this environment. We investigate the fixation probability of neutral bacterial mutants within a minimal model of the gut that includes hydrodynamic flow and resulting gradients of food and bacterial concentrations. We find that this fixation probability is substantially increased, compared with an equivalent well-mixed system, in the regime where the profiles of food and bacterial concentration are strongly spatially dependent. Fixation probability then becomes independent of total population size. We show that our results can be rationalized by introducing an active population, which consists of those bacteria that are actively consuming food and dividing. The active population size yields an effective population size for neutral mutant fixation probability in the gut.
肠道微生物群具有重要的遗传多样性，肠道的特定空间特征可能会影响该环境内的进化。我们研究了在包含水动力流以及食物和细菌浓度梯度的肠道最小模型中，中性细菌突变体的固定概率。我们发现，与等效的完全混合系统相比，在食物和细菌浓度分布强烈依赖于空间的区域，这种固定概率大大增加。固定概率随后与总种群规模无关。我们表明，通过引入一个由积极消耗食物和分裂的细菌组成的活跃种群，我们可以对结果进行合理化解释。活跃种群的大小为肠道中中性突变体固定概率提供了一个有效的种群规模。
