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Cássia-Silva C, Freitas CG, Jardim L, Bacon CD, Collevatti RG. In situ radiation explains the frequency of dioecious palms on islands. ANNALS OF BOTANY 2021; 128:205-215. [PMID: 33949659 PMCID: PMC8324027 DOI: 10.1093/aob/mcab056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND AIMS Dioecy has evolved up to 5000 times in angiosperms, despite the potentially high intrinsic costs to unisexuality. Dioecy prevents inbreeding, which is especially relevant on isolated islands when gene pools are small. Dioecy is also associated with certain dispersal traits, such as fruit size and type. However, the influence of dioecy on other life history traits and island distribution remains poorly understood. Here, we test the effect of dioecy on palm (Arecaceae) speciation rates, fruit size and frequency on islands. METHODS We used phylogenetic comparative methods to estimate the ancestral state of the sexual system and its impact on speciation rates and fruit size. Frequency of sexual systems, effect of insularity on the probability of being dioecious, and phylogenetic clustering of island dioecious vs. mainland species were inferred. Lastly, we determined the interplay of insularity and sexual system on speciation rates. KEY RESULTS Palms repeatedly evolved different sexual systems (dioecy, monoecy and polygamy) from a hermaphrodite origin. Differences in speciation rates and fruit size among the different sexual systems were not identified. An effect of islands on the probability of the palms being dioecious was also not found. However, we found a high frequency and phylogenetic clustering of dioecious palms on islands, which were not correlated with higher speciation rates. CONCLUSIONS The high frequency and phylogenetic clustering may be the result of in situ radiation and suggest an 'island effect' for dioecious palms, which was not explained by differential speciation rates. This island effect also cannot be attributed to long-distance dispersal due to the lack of fruit size difference among sexual systems, and particularly because palm dispersal to islands is highly constrained by the interaction between the sizes of fruit and frugivores. Taken together, we suggest that trait flexibility in sexual system evolution and the in situ radiation of dioecious lineages are the underlying causes of the outstanding distribution of palms on islands.
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Affiliation(s)
- Cibele Cássia-Silva
- Laboratório de Genética & Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Cíntia G Freitas
- Pós-Graduação em Ecologia e Conservação, Setor de Ciências Biológicas, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Lucas Jardim
- Laboratório de Ecologia Teórica e Síntese, Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Christine D Bacon
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Gothenburg, Sweden
| | - Rosane G Collevatti
- Laboratório de Genética & Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
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Muyle A, Martin H, Zemp N, Mollion M, Gallina S, Tavares R, Silva A, Bataillon T, Widmer A, Glémin S, Touzet P, Marais GAB. Dioecy Is Associated with High Genetic Diversity and Adaptation Rates in the Plant Genus Silene. Mol Biol Evol 2021; 38:805-818. [PMID: 32926156 PMCID: PMC7947750 DOI: 10.1093/molbev/msaa229] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
About 15,000 angiosperm species (∼6%) have separate sexes, a phenomenon known as dioecy. Why dioecious taxa are so rare is still an open question. Early work reported lower species richness in dioecious compared with nondioecious sister clades, raising the hypothesis that dioecy may be an evolutionary dead-end. This hypothesis has been recently challenged by macroevolutionary analyses that detected no or even positive effect of dioecy on diversification. However, the possible genetic consequences of dioecy at the population level, which could drive the long-term fate of dioecious lineages, have not been tested so far. Here, we used a population genomics approach in the Silene genus to look for possible effects of dioecy, especially for potential evidence of evolutionary handicaps of dioecy underlying the dead-end hypothesis. We collected individual-based RNA-seq data from several populations in 13 closely related species with different sexual systems: seven dioecious, three hermaphroditic, and three gynodioecious species. We show that dioecy is associated with increased genetic diversity, as well as higher selection efficacy both against deleterious mutations and for beneficial mutations. The results hold after controlling for phylogenetic inertia, differences in species census population sizes and geographic ranges. We conclude that dioecious Silene species neither show signs of increased mutational load nor genetic evidence for extinction risk. We discuss these observations in the light of the possible demographic differences between dioecious and self-compatible hermaphroditic species and how this could be related to alternatives to the dead-end hypothesis to explain the rarity of dioecy.
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Affiliation(s)
- Aline Muyle
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
- Department of Ecology and Evolutionary Biology, UC Irvine, Irvine, CA
| | - Hélène Martin
- University of Lille, CNRS, UMR 8198—Evo-Eco-Paleo, F-59000 Lille, France
- Département de Biologie, Institut de Biologie Integrative et des Systèmes, Université Laval, Québec, QC, Canada
| | - Niklaus Zemp
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Genetic Diversity Centre (GDC), ETH Zurich, Zurich, Switzerland
| | - Maéva Mollion
- Bioinformatics Research Centre, Aarhus University, Aarhus C, Denmark
| | - Sophie Gallina
- University of Lille, CNRS, UMR 8198—Evo-Eco-Paleo, F-59000 Lille, France
| | - Raquel Tavares
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Alexandre Silva
- Centro de Interpretação da Serra da Estrela (CISE), Seia, Portugal
| | - Thomas Bataillon
- Bioinformatics Research Centre, Aarhus University, Aarhus C, Denmark
| | - Alex Widmer
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Sylvain Glémin
- CNRS, ECOBIO [(Ecosystèmes, Biodiversité, Évolution)]—UMR 6553, University of Rennes, Rennes, France
- Department of Ecology and Genetics, Evolutionary Biology Center and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Pascal Touzet
- University of Lille, CNRS, UMR 8198—Evo-Eco-Paleo, F-59000 Lille, France
| | - Gabriel A B Marais
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
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3
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Tahir D, Glémin S, Lascoux M, Kaj I. Modeling a trait-dependent diversification process coupled with molecular evolution on a random species tree. J Theor Biol 2018; 461:189-203. [PMID: 30340056 DOI: 10.1016/j.jtbi.2018.10.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 10/10/2018] [Accepted: 10/12/2018] [Indexed: 12/23/2022]
Abstract
Understanding the evolution of binary traits, which affects the birth and survival of species and also the rate of molecular evolution, remains challenging. In this work, we present a probabilistic modeling framework for binary trait, random species trees, in which the number of species and their traits are represented by an asymmetric, two-type, continuous time Markov branching process. The model involves a number of different parameters describing both character and molecular evolution on the so-called 'reduced' tree, consisting of only extant species at the time of observation. We expand our model by considering the impact of binary traits on dN/dS, the normalized ratio of nonsynonymous to synonymous substitutions. We also develop mechanisms which enable us to understand the substitution rates on a phylogenetic tree with regards to the observed traits. The properties obtained from the model are illustrated with a phylogeny of outcrossing and selfing plant species, which allows us to investigate not only the branching tree rates, but also the molecular rates and the intensity of selection.
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Affiliation(s)
- Daniah Tahir
- Department of Mathematics, Uppsala University, Box 480, Uppsala SE-751 06, Sweden.
| | - Sylvain Glémin
- Department of Plant Ecology and Evolution, Uppsala University, Norbyvägen 18D, Uppsala SE-752 36, Sweden; UMR 5554 ISEM (Université de Montpellier-CNRS-IRD-EPHE), Montpellier Cedex 5 FR-34095, France.
| | - Martin Lascoux
- Department of Plant Ecology and Evolution, Uppsala University, Norbyvägen 18D, Uppsala SE-752 36, Sweden.
| | - Ingemar Kaj
- Department of Mathematics, Uppsala University, Box 480, Uppsala SE-751 06, Sweden.
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Muyle A, Käfer J, Zemp N, Mousset S, Picard F, Marais GA. SEX-DETector: A Probabilistic Approach to Study Sex Chromosomes in Non-Model Organisms. Genome Biol Evol 2016; 8:2530-43. [PMID: 27492231 PMCID: PMC5010906 DOI: 10.1093/gbe/evw172] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We propose a probabilistic framework to infer autosomal and sex-linked genes from RNA-seq data of a cross for any sex chromosome type (XY, ZW, and UV). Sex chromosomes (especially the non-recombining and repeat-dense Y, W, U, and V) are notoriously difficult to sequence. Strategies have been developed to obtain partially assembled sex chromosome sequences. Most of them remain difficult to apply to numerous non-model organisms, either because they require a reference genome, or because they are designed for evolutionarily old systems. Sequencing a cross (parents and progeny) by RNA-seq to study the segregation of alleles and infer sex-linked genes is a cost-efficient strategy, which also provides expression level estimates. However, the lack of a proper statistical framework has limited a broader application of this approach. Tests on empirical Silene data show that our method identifies 20-35% more sex-linked genes than existing pipelines, while making reliable inferences for downstream analyses. Approximately 12 individuals are needed for optimal results based on simulations. For species with an unknown sex-determination system, the method can assess the presence and type (XY vs. ZW) of sex chromosomes through a model comparison strategy. The method is particularly well optimized for sex chromosomes of young or intermediate age, which are expected in thousands of yet unstudied lineages. Any organisms, including non-model ones for which nothing is known a priori, that can be bred in the lab, are suitable for our method. SEX-DETector and its implementation in a Galaxy workflow are made freely available.
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Affiliation(s)
- Aline Muyle
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Jos Käfer
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Niklaus Zemp
- Institute of Integrative Biology (IBZ), ETH Zurich, Zürich, Switzerland
| | - Sylvain Mousset
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Franck Picard
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Gabriel Ab Marais
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
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Casimiro-Soriguer I, Buide ML, Narbona E. Diversity of sexual systems within different lineages of the genus Silene. AOB PLANTS 2015; 7:plv037. [PMID: 25862920 PMCID: PMC4433491 DOI: 10.1093/aobpla/plv037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/26/2015] [Indexed: 05/15/2023]
Abstract
Species and populations can be categorized by their sexual systems, depending on the spatial distribution of female and male reproductive structures within and among plants. Although a high diversity of sexual systems exists in Silene, their relative frequency at the genus and infrageneric level is unknown. Here, we carried out an extensive literature search for direct or indirect descriptions of sexual systems in Silene species. We found descriptions of sexual systems for 98 Silene species, where 63 and 35 correspond to the phylogenetically supported subgenera Silene and Behenantha, respectively. Hermaphroditism was the commonest sexual system (58.2 %), followed by dioecy (14.3 %), gynodioecy (13.3 %) and gynodioecy-gynomonoecy (i.e. hermaphroditic, female and gynomonoecious plants coexisting in the same population; 12.2 %). The presence of these sexual systems in both subgenera suggests their multiple origins. In 17 species, the description of sexual systems varied, and in most cases these differences corresponded to variations within or among populations. Interestingly, the poorly studied gynodioecy-gynomonoecy sexual system showed similar frequency to dioecy and gynodioecy in both subgenera. In addition, the incidence of gynodioecy-gynomonoecy was analysed in the species of section Psammophilae (Silene littorea, S. psammitis, S. adscendens and S. cambessedesii), in a survey of 26 populations across the distribution area of the species. The four species showed gynomonoecy-gynodioecy in most populations. Hermaphrodites were the most frequent morph, with a low number of females and gynomonoecious plants in all populations. The frequency of sexual morphs varied significantly among the studied populations but not among species. Female plants generally produced smaller numbers of flowers than hermaphroditic or gynomonoecious plants, and the percentages of female flowers per population were low. All these findings suggest that the gynodioecious-gynomonoecious sexual system in section Psammophilae is closer to hermaphroditism or gynomonoecy than gynodioecy.
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Affiliation(s)
- Inés Casimiro-Soriguer
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Ctra. de Utrera, km 1, 41013 Sevilla, Spain Área de Botánica, Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Avenida Reina Mercedes s/n, 41012 Sevilla, Spain
| | - Maria L Buide
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Ctra. de Utrera, km 1, 41013 Sevilla, Spain
| | - Eduardo Narbona
- Área de Botánica, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Ctra. de Utrera, km 1, 41013 Sevilla, Spain
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6
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Abstract
Dioecy (separate male and female individuals) ensures outcrossing and is more prevalent in animals than in plants. Although it is common in bryophytes and gymnosperms, only 5% of angiosperms are dioecious. In dioecious higher plants, flowers borne on male and female individuals are, respectively deficient in functional gynoecium and androecium. Dioecy is inherited via three sex chromosome systems: XX/XY, XX/X0 and WZ/ZZ, such that XX or WZ is female and XY, X0 or ZZ are males. The XX/XY system generates the rarer XX/X0 and WZ/ZZ systems. An autosome pair begets XY chromosomes. A recessive loss-of-androecium mutation (ana) creates X chromosome and a dominant gynoecium-suppressing (GYS) mutation creates Y chromosome. The ana/ANA and gys/GYS loci are in the sex-determining region (SDR) of the XY pair. Accumulation of inversions, deleterious mutations and repeat elements, especially transposons, in the SDR of Y suppresses recombination between X and Y in SDR, making Y labile and increasingly degenerate and heteromorphic from X. Continued recombination between X and Y in their pseudoautosomal region located at the ends of chromosomal arms allows survival of the degenerated Y and of the species. Dioecy is presumably a component of the evolutionary cycle for the origin of new species. Inbred hermaphrodite species assume dioecy. Later they suffer degenerate-Y-led population regression. Cross-hybridization between such extinguishing species and heterologous species, followed by genome duplication of segregants from hybrids, give rise to new species.
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7
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Castric V, Billiard S, Vekemans X. Trait transitions in explicit ecological and genomic contexts: plant mating systems as case studies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 781:7-36. [PMID: 24277293 DOI: 10.1007/978-94-007-7347-9_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Plants are astonishingly diverse in how they reproduce sexually, and the study of plant mating systems provides some of the most compelling cases of parallel and independent evolutionary transitions. In this chapter, we review how the massive amount of genomic data being produced is allowing long-standing predictions from ecological and evolutionary theory to be put to test. After a review of theoretical predictions about the importance of considering the genomic architecture of the mating system, we focus on a set of recent discoveries on how the mating system is controlled in a variety of model and non-model species. In parallel, genomic approaches have revealed the complex interaction between the evolution of genes controlling mating systems and genome evolution, both genome-wide and in the mating system control region. In several cases, major transitions in the mating system can be clearly associated with important ecological changes, hence illuminating an important interplay between ecological and genomic approaches. We also list a number of major unsolved questions that remain for the field, and highlight foreseeable conceptual developments that are likely to play a major role in our understanding of how plant mating systems evolve in Nature.
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Affiliation(s)
- Vincent Castric
- Laboratoire de Génétique et Evolution des Populations Végétales (GEPV), UMR 8198; CNRS, Université Lille 1, Sciences et Technologies, Cité Scientifique, Villeneuve d'Ascq, France,
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8
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Käfer J, Mousset S. Standard sister clade comparison fails when testing derived character States. Syst Biol 2014; 63:601-9. [PMID: 24671619 DOI: 10.1093/sysbio/syu024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Comparing species richness in sister clades that differ in a character state is one of the ways to study factors influencing diversification. While most of its applications have focussed on traits that increase diversification, some have been used to study the association of a trait with lower species richness, e.g., the occurrence of dioecy in flowering plants. We show here, using simulations and an analytical model, that the null expectation of equal species richness that is generally used in sister clade comparisons is wrong in the case of a derived trait occurring independently from speciation: one should expect fewer species in the clade with the derived character state when there is no difference in diversification rates. This is due to the waiting time for the derived state to appear, which causes it to occur more often on longer branches. This has the important implication that the probability for a clade to possess the derived state depends on the tree geometry, and thus on species richness: species-poorer clades are more likely to possess the derived state. We develop a statistical test for sister clade comparisons to study the effect of a derived character state. Applying it to a data set of dioecious clades, we find that we cannot confirm earlier work that concluded that dioecy decreases diversification; on the contrary, it seems to be associated to higher species richness than expected. [angiosperms; dioecy; diversification; sister clades; species richness.].
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Affiliation(s)
- Jos Käfer
- Université de Lyon; Université Lyon 1; CNRS; UMR 5558; Laboratoire de Biométrie et Biologie Evolutive; F-69622, Villeurbanne, France
| | - Sylvain Mousset
- Université de Lyon; Université Lyon 1; CNRS; UMR 5558; Laboratoire de Biométrie et Biologie Evolutive; F-69622, Villeurbanne, France
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Slancarova V, Zdanska J, Janousek B, Talianova M, Zschach C, Zluvova J, Siroky J, Kovacova V, Blavet H, Danihelka J, Oxelman B, Widmer A, Vyskot B. Evolution of sex determination systems with heterogametic males and females in silene. Evolution 2013; 67:3669-77. [PMID: 24299418 DOI: 10.1111/evo.12223] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 07/29/2013] [Indexed: 02/03/2023]
Abstract
The plant genus Silene has become a model for evolutionary studies of sex chromosomes and sex-determining mechanisms. A recent study performed in Silene colpophylla showed that dioecy and the sex chromosomes in this species evolved independently from those in Silene latifolia, the most widely studied dioecious Silene species. The results of this study show that the sex-determining system in Silene otites, a species related to S. colpophylla, is based on female heterogamety, a sex determination system that is unique among the Silene species studied to date. Our phylogenetic data support the placing of S. otites and S. colpophylla in the subsection Otites and the analysis of ancestral states suggests that the most recent common ancestor of S. otites and S. colpophylla was most probably dioecious. These observations imply that a switch from XX/XY sex determination to a ZZ/ZW system (or vice versa) occurred in the subsection Otites. This is the first report of two different types of heterogamety within one plant genus of this mostly nondioecious plant family.
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Affiliation(s)
- Veronika Slancarova
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, CZ-612 65, Brno, Czech Republic
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Disentangling the effects of mating systems and mutation rates on cytoplasmic [correction of cytoplamic] diversity in gynodioecious Silene nutans and dioecious Silene otites. Heredity (Edinb) 2013; 111:157-64. [PMID: 23591518 DOI: 10.1038/hdy.2013.32] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 02/14/2013] [Accepted: 03/05/2013] [Indexed: 01/11/2023] Open
Abstract
Many flowering plant species exhibit a variety of distinct sexual morphs, the two most common cases being the co-occurrence of females and males (dioecy) or the co-occurrence of hermaphrodites and females (gynodioecy). In this study, we compared DNA sequence variability of the three genomes (nuclear, mitochondrial and chloroplastic) of a gynodioecious species, Silene nutans, with that of a closely related dioecious species, Silene otites. In the light of theoretical models, we expect cytoplasmic diversity to differ between the two species due to the selective dynamics that acts on cytoplasmic genomes in gynodioecious species: under an epidemic scenario, the gynodioecious species is expected to exhibit lower cytoplasmic diversity than the dioecious species, while the opposite is expected in the case of balancing selection maintaining sterility cytoplasms in the gynodioecious species. We found no difference between the species for nuclear gene diversity, but, for the cytoplasmic loci, the gynodioecious S. nutans had more haplotypes, and higher nucleotide diversity, than the dioecious relative, S. otites, even though the latter has a relatively high rate of mitochondrial synonymous substitutions, and therefore presumably a higher mutation rate. Therefore, as the mitochondrial mutation rate cannot account for the higher cytoplasmic diversity found in S. nutans, our findings support the hypothesis that gynodioecy in S. nutans has been maintained by balancing selection rather than by epidemic-like dynamics.
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