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 factors that influence effective population number. Here, a range of reproductive systems (full gonochorism, full hermaphroditism, androdioecy, and gynodioecy) are compared with respect to the maintenance of neutral genetic diversity. The analysis assumes anisogamy, with reproduction limited by the availability of large gametes (ova or seeds) but not small gametes (sperm or pollen). Levels of neutral genetic diversity respond to the relative proportions of gonochores and hermaphrodites in different ways under androdioecy versus gynodioecy. The manner in which effective number, sex-specific viability differences, and the evolving quantitative trait of the population influence the level of neutral genetic diversity is described across the systems of reproduction studied.