title: Karyotypic changes through dysploidy persist longer over evolutionary time than polyploid changes.
abstract: Chromosome evolution has been demonstrated to have profound effects on diversification rates and speciation in angiosperms. While polyploidy has predated some major radiations in plants, it has also been related to decreased diversification rates. There has been comparatively little attention to the evolutionary role of gains and losses of single chromosomes, which may or not entail changes in the DNA content (then called aneuploidy or dysploidy, respectively). In this study we investigate the role of chromosome number transitions and of possible associated genome size changes in angiosperm evolution. We model the tempo and mode of chromosome number evolution and its possible correlation with patterns of cladogenesis in 15 angiosperm clades. Inferred polyploid transitions are distributed more frequently towards recent times than single chromosome gains and losses. This is likely because the latter events do not entail changes in DNA content and are probably due to fission or fusion events (dysploidy), as revealed by an analysis of the relationship between genome size and chromosome number. Our results support the general pattern that recently originated polyploids fail to persist, and suggest that dysploidy may have comparatively longer-term persistence than polyploidy. Changes in chromosome number associated with dysploidy were typically observed across the phylogenies based on a chi-square analysis, consistent with these changes being neutral with respect to diversification.
authors.affiliation: Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain ; Herbarium, The Morton Arboretum, Lisle, Illinois, United States of America ; Botany, The Field Museum, Chicago, Illinois, United States of America.
authors.forename: Marcial
authors.initials: M
authors.lastname: Escudero
authors.affiliation: Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Martín-Bravo
authors.affiliation: Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Itay
authors.initials: I
authors.lastname: Mayrose
authors.affiliation: Biodiversity and Conservation, Real Jardín Botánico CSIC, Madrid, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: Fernández-Mazuecos
authors.affiliation: Systematic Biology, Uppsala University, Uppsala, Sweden.
authors.forename: Omar
authors.initials: O
authors.lastname: Fiz-Palacios
authors.affiliation: Herbarium, The Morton Arboretum, Lisle, Illinois, United States of America ; Botany, The Field Museum, Chicago, Illinois, United States of America.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Hipp
authors.affiliation: Plant and Animal Biology and Ecology, University of A Coruña, A Coruña, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Pimentel
authors.affiliation: Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain ; Biodiversity and Conservation, Real Jardín Botánico CSIC, Madrid, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Jiménez-Mejías
authors.affiliation: Biology, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Valcárcel
authors.affiliation: Biodiversity and Conservation, Real Jardín Botánico CSIC, Madrid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Vargas
authors.affiliation: Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Seville, Spain.
authors.forename: Modesto
authors.initials: M
authors.lastname: Luceño
mesh_terms: D000782:Aneuploidy; D032461:Chromosomes, Plant / Q000737:chemistry*; D018744:DNA, Plant / Q000145:classification / Q000235:genetics*; D049810:Genetic Speciation; D059646:Genome Size; D018745:Genome, Plant; D007621:Karyotyping; D019684:Magnoliopsida / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D011123:Polyploidy
chemical_list: D018744:DNA, Plant