Data from: Mutation accumulation and the formation of range limits

The dynamics of range formation are important for understanding and
predicting species distributions. Here, we focus on a process that has
thus far been overlooked in the context of range formation; the
accumulation of mutation load. We find that mutation accumulation severely
reduces the extent of a range across an environmental gradient, especially
when dispersal is limited, growth rate is low and mutations are of
intermediate deleterious effect. Our results illustrate the important role
deleterious mutations can play in range formation. We highlight this as a
necessary focus for further work, noting particularly the potentially
conflicting effects dispersal may have in reducing mutation load and
simultaneously increasing migration load in marginal populations.