Fig 1. Moran Birth-death and death-Birth processes on a population structure.

a, Each node is occupied by a resident with fitness 1 (blue), or a mutant with fitness r ≥ 1 (red). Thicker edges denote higher edge weights (stronger interactions). b, In Moran Birth-death process, a random individual reproduces, and the produced offspring migrates along a random edge. c, In Moran death-Birth process, a random individual dies, and the vacancy is filled by a random neighbor. In both cases, edges with higher weight are selected more often, and fitness plays a role in the Birth step but not in the death step.