Toward a universal model for spatially structured populations

TL;DR

This paper introduces a universal graph-based model for spatially structured populations, showing how migration asymmetry influences mutant fixation probabilities and can be experimentally tuned.

Contribution

It generalizes previous models by decoupling migration from birth and death, revealing universal effects of migration asymmetry on natural selection in structured populations.

Findings

Star graph can switch from amplifying to suppressing selection

Migration asymmetry determines fixation probabilities

Model's results are independent of microscopic dynamics

Abstract

A key question in evolution is how likely a mutant is to take over. This depends on natural selection and on stochastic fluctuations. Population spatial structure can impact mutant fixation probabilities. We introduce a model for structured populations on graphs that generalizes previous ones by making migrations independent of birth and death. We demonstrate that by tuning migration asymmetry, the star graph transitions from amplifying to suppressing natural selection. The results from our model are universal in the sense that they do not hinge on a modeling choice of microscopic dynamics or update rules. Instead, they depend on migration asymmetry, which can be experimentally tuned and measured.