How timing and mode of selection shape ancestral genetic contributions

Abstract

We examine a population that evolves according to a biparental Moran model with two distinct types of individuals. Each individual's type is determined by the allele they carry at one biallelic locus, which is transmitted in a Mendelian way. This type influences the individual's mating preferences. We investigate two specific mating patterns: (i) where the type determines the level of attractiveness, and (ii) where the type dictates the level of homogamous choosiness. In both scenarios, one type has an advantage over the other. Assuming an initial proportion b of individuals are of the advantaged type, we give an explicit formula for the asymptotic proportion of the population's genome that originates from these advantaged ancestors under an infinite population size approximation. Our results enable a comparison of the relative strengths of homogamous choosiness, attractiveness, and viability selection in terms of genome transmission, and prove notably that viability selection is always more efficient than both forms of reproductive selection.