Before revision:  Under weak selection, meaning a small perturbation of the neutral model, we give a general first-order expansion of a mutant's fixation probability for an arbitrary initial configuration of mutant and resident types.
After revision:  This fixation probability is difficult to compute in general, as it depends on the mutation's effect on URLanism as well as the population's spatial structure, mating patterns, and other factors. Here we consider weak selection, meaning a small perturbation of the neutral model, we give a general first-order expansion of a mutant's fixation probability for an arbitrary initial configuration of mutant and resident types.