Linkage and the limits to natural selection

We review the various factors that limit adaptation by natural selection. Recent discussion of constraints on selection and, conversely, of the factors that enhance ‘‘evolvability’’, have concentrated on the kinds of varia-tion that can be produced. Here, we emphasise that adaptation depends on how the various evolutionary processes shape variation in populations. We survey the limits that population genetics places on adaptive evolu-tion, and discuss the relationship between disparate literatures. BioEssays 22:1075–1084, 2000