Data from: Evolutionary dynamics of a quantitative trait in a finite asexual population

In finite populations, mutation limitation and genetic drift can hinder
evolutionary diversification. We consider the evolution of a quantitative
trait in an asexual population whose size can vary and depends explicitly
on the trait. Previous work showed that evolutionary branching is certain
(“deterministic branching”) above a threshold population size, but
uncertain (“stochastic branching”) below it. Using the stationary
distribution of the population’s trait variance, we identify three
qualitatively different sub-domains of “stochastic branching” and
illustrate our results using a model of social evolution. We find that in
very small populations, branching will almost never be observed; in
intermediate populations, branching is intermittent, arising and
disappearing over time; in larger populations, finally, branching is
expected to occur and persist for substantial periods of time. Our study
provides a clearer picture of the ecological conditions that facilitate
the appearance and persistence of novel evolutionary lineages in the face
of genetic drift.