The rate of polygenic mutation

Abstract

SummaryBy application of the neutral model of phenotypic evolution, quantitative estimates of the rate of input of genetic variance by polygenic mutation can be extracted from divergence experiments as well as from the response of an inbred base population to selection. The analytical methods are illustrated through a survey of data on a diversity of organisms includingDrosophila, Tribolium, mice, and several crop species. The mutational rate of introduction of genetic variance (Vm) scaled by the environmental variance (VE) is shown to vary between populations, species, and characters with a range of approximately 10−4to 5 × 10−2.Vm/VEforDrosophilaviability is somewhat below this range, while hybrid dysgenesis may temporarily inflateVm/VEbeyond 10−1. Potential sources of bias and error in the estimation ofVmare discussed, as are the practical implications of the observed limits toVm/VEfor projecting the long-term response to selection and for testing adaptational hypotheses.