The principle of random union of gametes in a finite population

Abstract

Two non-overlapping-generation models for the evolution of the genetic structure of a random-mating population in respect of a set of homologous chromosomes are considered. The models refer to a finite population (the first traces zygotic structure from generation to generation; the second — gametic structure) at suitable time points. The two models are reconciled (a stochastic principle of random union of gametes is shown to hold) by a combinatorial argument. For a two-locus diploid diallelic situation in the absence of selection and mutation, asymptotic behaviour is considered and fixation probabilities are derived.