Distributions of Time to Fixation of Neutral Genes

Abstract

Exact distributions of times to fixation are derived for neutral alleles in a discrete generation, constant census model that accommodates specified variations in gametic contributions per parent. This enables an evaluation of the performance of the effective number concept, and of diffusion equation approximations, used to characterize the time scale of drift events. Following simultaneous comparisons of modes, medians, means and standard deviations of exact and approximate distributions of times to fixation, it is concluded that diffusion equation methods, in conjunction with the appropriate effective number, do produce accurate results.