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Evolution in bacterial expanding populations
In this work, I focus on the evolution of expanding populations, such as bacterial colonies or cancerous tumors. If population expansion is driven by growth and dispersal, then the evolutionary fate of a mutant should also depend on both growth and dispersal. Since these two traits are often constrained by a trade-off, one asks which one will be favored by evolution. For instance, is moving faster and growing slower a good strategy ? Starting with the Fisher-KPP equation, I come up with a quantitative evolutionary rule, which depends only on growth and dispersal rates of the ancestor and the mutant. Theoretical findings are supported by experiments with bacterial swarming colonies, as well as data from ecology literature.