Modeling spatial evolution of multi-drug resistance under drug environmental gradients
Fig 2
Coexistence example of 2 strains everywhere in space for space-dependent gi(z) which are mutually symmetric about L/2.
A. In this case, one strain is better-adapted in the first half of the domain, the other strain is better-adapted in the second-half of the domain with the selective advantages exactly counterbalanced. B. For low diffusion, the two strains coexist such that each strain dominates in frequency in the part of the domain where it experiences a relatively higher growth rate, maintaining a high-degree of spatial segregation in the system. C. As diffusion increases, the coexistence frequencies become more similar and tend towards 1/2 in both halves of the domain. D. Eventually, for very high-diffusion, the growth variation starts to matter less and less, and the two strains tend to the same frequency everywhere, leading to a uniformly homogeneous spatial distribution of diversity over space.