The Evolution of Mutualism in Gut Microbiota Via Host Epithelial Selection
Figure 4
Selectivity amplification by the host epithelium.
Weak epithelial selection dominates strong lumen selection. Strain B has a 100% growth rate advantage on nutrients from the lumen, and lumen nutrients are five times the concentration as epithelial nutrients. Grey planes mark the starting frequency of the two strains (0.5). (A) Host nutrients provide growth rate advantages to strain A ranging from 1% to 100%. (B) The host secretes antimicrobials that preferentially kill strain B; susceptibility advantages for strain A range from 1% to 100%. Host-secreted nutrients are also provided that neutral. In (A) and (B) strain A outcompetes strain B for all but the smallest selective advantages.