title: Coalescent Times and Patterns of Genetic Diversity in Species with Facultative Sex: Effects of Gene Conversion, Population Structure, and Heterogeneity.
abstract: Many diploid organisms undergo facultative sexual reproduction. However, little is currently known concerning the distribution of neutral genetic variation among facultative sexual organisms except in very simple cases. Understanding this distribution is important when making inferences about rates of sexual reproduction, effective population size, and demographic history. Here we extend coalescent theory in diploids with facultative sex to consider gene conversion, selfing, population subdivision, and temporal and spatial heterogeneity in rates of sex. In addition to analytical results for two-sample coalescent times, we outline a coalescent algorithm that accommodates the complexities arising from partial sex; this algorithm can be used to generate multisample coalescent distributions. A key result is that when sex is rare, gene conversion becomes a significant force in reducing diversity within individuals. This can reduce genomic signatures of infrequent sex (i.e., elevated within-individual allelic sequence divergence) or entirely reverse the predicted patterns. These models offer improved methods for assessing null patterns of molecular variation in facultative sexual organisms.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada M5S 3B2 Bioinformatics Research Centre, University of Aarhus, 8000C Aarhus, Denmark matthew.hartfield@utoronto.ca.
authors.forename: Matthew
authors.initials: M
authors.lastname: Hartfield
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada M5S 3B2.
authors.forename: Stephen I
authors.initials: SI
authors.lastname: Wright
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada M5S 3B2.
authors.forename: Aneil F
authors.initials: AF
authors.lastname: Agrawal
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004171:Diploidy; D005785:Gene Conversion; D018740:Genetic Heterogeneity; D014644:Genetic Variation; D062312:Islands; D008954:Models, Biological; D010312:Parthenogenesis; D011157:Population Dynamics; D012098:Reproduction; D057945:Self-Fertilization; D012723:Sex; D013995:Time
keywords: facultative sex; gene conversion; genealogies; heterogeneity in sex; migration