Digest: The complex interplay of phenotypic variation and diversifying selection.

How does diversity arise, and how is it maintained? In a model of microbial competition, Amicone and Gordo find that frequent mutations and the effects of genetic drift generate sufficient phenotypic variation to alter selection such that resource specialists are favored, potentially paving the way for speciation. Their results highlight that processes affecting the distribution of genotypic and phenotypic variation may affect not only population responses to selection but also the direction of selection itself.