Neutral genetic diversity in mixed mating systems

Abstract

Systems of reproduction differ with respect to the magnitude of neutral genetic diversity maintained in a population. In particular, the partitioning of reproductives into mating types and regular inbreeding have long been recognized as key determinants of effective population number. Here, the Ewens Sampling Formula provides the framework for a comparison of a range of reproductive systems, including full gonochorism, full hermaphroditism, androdioecy, and gynodioecy. In addition, sex-specific viability differences and the evolving quantitative trait of the population sex ratio also influence the maintenance of genetic diversity. Under the assumption that the reproduction is limited by large gametes (eggs or seeds) and not by small gametes (sperm or pollen), the relative proportions of gonochores and hermaphrodites affect these various evolutionary processes and levels of neutral genetic diversity in different ways under androdioecy and gynodioecy.