title: On the origin and evolution of apomixis in Boechera.
abstract: The genetic mechanisms causing seed development by gametophytic apomixis in plants are predominantly unknown. As apomixis is consistently associated with hybridity and polyploidy, these confounding factors may either (a) be the underlying mechanism for the expression of apomixis, or (b) obscure the genetic factors which cause apomixis. To distinguish between these hypotheses, we analyzed the population genetic patterns of diploid and triploid apomictic lineages and their sexual progenitors in the genus Boechera (Brassicaceae). We find that while triploid apomixis is associated with hybridization, the majority of diploid apomictic lineages are likely the product of intra-specific crosses. We then show that these diploid apomicts are more likely to sire triploid apomictic lineages than conspecific sexuals. Combined with flow cytometric seed screen phenotyping for male and female components of apomixis, our analyses demonstrate that hybridization is an indirect correlate of apomixis in Boechera.
authors.affiliation: Apomixis Research Group, Leibniz Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstraße 3, 06466, Gatersleben, Germany.
authors.forename: John T
authors.initials: JT
authors.lastname: Lovell
authors.forename: Olawale M
authors.initials: OM
authors.lastname: Aliyu
authors.forename: Martin
authors.initials: M
authors.lastname: Mau
authors.forename: M Eric
authors.initials: ME
authors.lastname: Schranz
authors.forename: Marcus
authors.initials: M
authors.lastname: Koch
authors.forename: Christiane
authors.initials: C
authors.lastname: Kiefer
authors.forename: Bao-Hua
authors.initials: BH
authors.lastname: Song
authors.forename: Thomas
authors.initials: T
authors.lastname: Mitchell-Olds
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Sharbel
mesh_terms: D060832:Apomixis / Q000235:genetics*; D019607:Brassicaceae / Q000235:genetics* / Q000502:physiology; D004171:Diploidy; D005828:Genetics, Population; D005838:Genotype; D006824:Hybridization, Genetic; D010641:Phenotype; D012639:Seeds / Q000235:genetics / Q000502:physiology; D057885:Triploidy