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Van Drunen WE, Friedman J. Autopolyploid establishment depends on life-history strategy and the mating outcomes of clonal architecture. Evolution 2022; 76:1953-1970. [PMID: 35861365 DOI: 10.1111/evo.14582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 06/21/2022] [Accepted: 07/11/2022] [Indexed: 01/22/2023]
Abstract
Polyploidy is a significant component in the evolution of many taxa, particularly plant groups. However, new polyploids face substantial fitness disadvantages due to a lack of same-cytotype mates, and the factors promoting or preventing polyploid establishment in natural populations are often unclear. We develop spatially explicit agent-based simulation models to test the hypothesis that a perennial life history and clonal propagation facilitate the early stages of polyploid establishment and persistence. Our models show that polyploids are more likely to establish when they have longer life spans than diploids, especially when self-fertilization rates are high. Polyploids that combine sexual and clonal reproduction can establish across a wide range of life histories, but their success is moderated by clonal strategy. By tracking individuals and mating events, we reveal that clonal architecture has a substantial impact on the spatial structure of the mixed diploid-polyploid population during polyploid establishment: altering patterns of mating within or between cytotypes via geitonogamous self-fertilization, the mechanisms through which polyploid establishment proceeds, and the final composition of the polyploid population. Overall, our findings provide novel insight into the role of clonal structure in modulating the complex relationship between polyploidy, perenniality, and clonality and offer testable predictions for future empirical work.
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Affiliation(s)
- Wendy E Van Drunen
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.,Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Jannice Friedman
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
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Castro M, Loureiro J, Husband BC, Castro S. The role of multiple reproductive barriers: strong post-pollination interactions govern cytotype isolation in a tetraploid-octoploid contact zone. ANNALS OF BOTANY 2020; 126:991-1003. [PMID: 32353869 PMCID: PMC7596367 DOI: 10.1093/aob/mcaa084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/23/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Polyploidy is an important contributor to sympatric speciation and assortative mating is a key mechanism driving cytotype interactions in contact zones. While strong reproductive barriers can mediate the coexistence of different cytotypes in sympatry, positive frequency-dependent mating disadvantage ultimately drives the transition to single-ploidy populations. However, comprehensive estimates of reproductive isolation among cytotypes and across multiple barriers are rare. We quantify the strength of isolation across multiple reproductive stages in a tetraploid-octoploid contact zone to understand the potential for coexistence. METHODS Assortative mating due to flowering asynchrony, pollinator behaviour, morphological overlap, self-fertilization and gametic competition between tetraploid and octoploid Gladiolus communis in a contact zone in the Western Iberian Peninsula were assessed in natural and experimental populations to quantify reproductive isolation (RI) between cytotypes. KEY RESULTS Tetraploids and octoploids have a high degree of overlap in flowering time and similar floral morphology, and are visited by generalist insects without cytotype foraging preferences, resulting in weak pre-pollination RI (from 0.00 to 0.21). In contrast, post-pollination isolation resulting from gametic selection was a strong barrier to inter-cytotype mating, with ploidy composition in stigmatic pollen loads determining the levels of RI (from 0.54 to 1.00). Between-cytotype cross-incompatibility was relatively high (RI from 0.54 to 0.63) as was isolation acquired through self-pollination (RI of 0.59 in tetraploids and 0.39 in octoploids). CONCLUSIONS Total RI was high for both tetraploids (from 0.90 to 1.00) and octoploids (from 0.78 to 0.98). Such high rates of assortative mating will enable cytotype coexistence in mixed-ploidy populations by weakening the impacts of minority cytotype exclusion. This study reveals the key role of gametic selection in cytotype siring success and highlights the importance of comprehensive estimates across multiple reproductive barriers to understand cytotype interactions at contact zones.
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Affiliation(s)
- Mariana Castro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
| | - João Loureiro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Sílvia Castro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
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Morgan EJ, Čertner M, Lučanová M, Kubíková K, Marhold K, Kolář F. Niche similarity in diploid-autotetraploid contact zones of Arabidopsis arenosa across spatial scales. AMERICAN JOURNAL OF BOTANY 2020; 107:1375-1388. [PMID: 32974906 DOI: 10.1002/ajb2.1534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/21/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Whole genome duplication is a major evolutionary event, but its role in ecological divergence remains equivocal. When populations of different ploidy (cytotypes) overlap in space, "contact zones" are formed, allowing the study of evolutionary mechanisms contributing toward ploidy divergence. Multiple contact zones per species' range are often described but rarely leveraged as natural replicates. We explored whether the strength of niche differentiation of diploid and autotetraploid Arabidopsis arenosa varies over distinct contact zones and if the frequency of triploids decreases from seedling to adult stage. METHODS We characterized ploidy composition and habitat preferences in 264 populations across three contact zones using climatic niche modeling. Ecological differences of cytotypes were also assessed using local vegetation surveys at 110 populations within two contact zones, and at the finer scale within five mixed-ploidy sites. This was complemented by flow cytometry of seedlings. RESULTS We found no niche differences between diploid and tetraploid populations within contact zones for either climatic or local environmental variables. Comparisons of cytotypes within mixed-ploidy sites found weak niche differences that were inconsistent in direction. Triploid individuals were virtually absent (0.14%) in the field, and they were at a similarly low frequency (0.2%) in ex situ germinated seedlings. CONCLUSIONS This study demonstrates the strength in investigating different spatial scales across several contact zones when addressing ecological niche differentiation between ploidies. The lack of consistent habitat differentiation of ploidies across the scales and locations supports the recently emerging picture that processes other than ecological differentiation may underlie ploidy coexistence in diploid-autopolyploid systems.
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Affiliation(s)
- Emma J Morgan
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Magdalena Lučanová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 31, CZ-370 05, České Budějovice, Czech Republic
| | - Kateřina Kubíková
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
| | - Karol Marhold
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23, Bratislava, Slovak Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, AT-6020, Innsbruck, Austria
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Van Drunen WE, Husband BC. Evolutionary associations between polyploidy, clonal reproduction, and perenniality in the angiosperms. THE NEW PHYTOLOGIST 2019; 224:1266-1277. [PMID: 31215649 DOI: 10.1111/nph.15999] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/10/2019] [Indexed: 05/10/2023]
Abstract
Clonal reproduction is thought to facilitate polyploid establishment in the angiosperms, but the evolutionary relationship between polyploidy and clonality has not been thoroughly tested. A perennial life history may confer many of the same advantages, and the relative importance of clonality versus perenniality is unknown. We used phylogenetic comparative analyses of 1751 species to examine associations between polyploidy, clonality, and life history. We test hypotheses of co-evolution by determining the sequence of trait development. Polyploidy is associated with both clonality and perenniality across species, and analyses show that clonality can be an important predictor of polyploidy beyond perenniality. Tests of directionality on our full dataset suggest that polyploidy is more likely to promote clonality or perenniality than vice versa, although there are significant differences in patterns of co-evolution among major angiosperm groups. Our results suggest that polyploidy and clonal reproduction are evolutionarily associated across the angiosperms, even when perenniality is considered, but we find little evidence at the whole-angiosperm level for the hypothesis that clonality promotes polyploidy. However, variation among different clades indicates that polyploidy and clonality are interacting in diverse ways, likely to be due to the variable roles of clonality in their evolutionary histories.
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Affiliation(s)
- Wendy E Van Drunen
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
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Wos G, Mořkovská J, Bohutínská M, Šrámková G, Knotek A, Lučanová M, Španiel S, Marhold K, Kolář F. Role of ploidy in colonization of alpine habitats in natural populations of Arabidopsis arenosa. ANNALS OF BOTANY 2019; 124:255-268. [PMID: 31185073 PMCID: PMC6758580 DOI: 10.1093/aob/mcz070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/17/2019] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Polyploidy is an important driver of plant diversification and adaptation to novel environments. As a consequence of genome doubling, polyploids often exhibit greater colonizing ability or occupy a wider ecological niche than diploids. Although elevation has been traditionally considered as a key driver structuring ploidy variation, we do not know if environmental and phenotypic differentiation among ploidy cytotypes varies along an elevational gradient. Here, we tested for the consequences of genome duplication on genetic diversity, phenotypic variation and habitat preferences on closely related diploid and tetraploid populations that coexist along approx. 2300 m of varying elevation. METHODS We sampled and phenotyped 45 natural diploid and tetraploid populations of Arabidopsis arenosa in one mountain range in Central Europe (Western Carpathians) and recorded abiotic and biotic variables at each collection site. We inferred genetic variation, population structure and demographic history in a sub-set of 29 populations genotyped for approx. 36 000 single nucleotide polymorphisms. KEY RESULTS We found minor effects of polyploidy on colonization of alpine stands and low genetic differentiation between the two cytotypes, mirroring recent divergence of the polyploids from the local diploid lineage and repeated reticulation events among the cytotypes. This pattern was corroborated by the absence of ecological niche differentiation between the two cytotypes and overall phenotypic similarity at a given elevation. CONCLUSIONS The case of A. arenosa contrasts with previous studies that frequently showed clear niche differentiation between cytotypes. Our work stresses the importance of considering genetic structure and past demographic processes when interpreting the patterns of ploidy distributions, especially in species that underwent recent polyploidization events.
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Affiliation(s)
- Guillaume Wos
- Department of Botany, Charles University, Prague, Czech Republic
| | - Jana Mořkovská
- Department of Botany, Charles University, Prague, Czech Republic
| | - Magdalena Bohutínská
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
| | | | - Adam Knotek
- Department of Botany, Charles University, Prague, Czech Republic
| | - Magdalena Lučanová
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
| | - Stanislav Španiel
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Karol Marhold
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Filip Kolář
- Department of Botany, Charles University, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
- Institute of Botany, University of Innsbruck, Innsbruck, Austria
- For correspondence. E-mail
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Hanušová K, Čertner M, Urfus T, Koutecký P, Košnar J, Rothfels CJ, Jarolímová V, Ptáček J, Ekrt L. Widespread co-occurrence of multiple ploidy levels in fragile ferns (Cystopteris fragilis complex; Cystopteridaceae) probably stems from similar ecology of cytotypes, their efficient dispersal and inter-ploidy hybridization. ANNALS OF BOTANY 2019; 123:845-855. [PMID: 30541055 PMCID: PMC6526313 DOI: 10.1093/aob/mcy219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 11/09/2018] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Polyploidy has played an important role in the evolution of ferns. However, the dearth of data on cytotype diversity, cytotype distribution patterns and ecology in ferns is striking in comparison with angiosperms and prevents an assessment of whether cytotype coexistence and its mechanisms show similar patterns in both plant groups. Here, an attempt to fill this gap was made using the ploidy-variable and widely distributed Cystopteris fragilis complex. METHODS Flow cytometry was used to assess DNA ploidy level and monoploid genome size (Cx value) of 5518 C. fragilis individuals from 449 populations collected over most of the species' global distributional range, supplemented with data from 405 individuals representing other related species from the complex. Ecological preferences of C. fragilis tetraploids and hexaploids were compared using field-recorded parameters and database-extracted climate data. KEY RESULTS Altogether, five different ploidy levels (2x, 4x, 5x, 6x, 8x) were detected and three species exhibited intraspecific ploidy-level variation: C. fragilis, C. alpina and C. diaphana. Two predominant C. fragilis cytotypes, tetraploids and hexaploids, co-occur over most of Europe in a diffuse, mosaic-like pattern. Within this contact zone, 40 % of populations were mixed-ploidy and most also contained pentaploid hybrids. Environmental conditions had only a limited effect on the distribution of cytotypes. Differences were found in the Cx value of tetraploids and hexaploids: between-cytotype divergence was higher in uniform-ploidy than in mixed-ploidy populations. CONCLUSIONS High ploidy-level diversity and widespread cytotype coexistence in the C. fragilis complex match the well-documented patterns in some angiosperms. While ploidy coexistence in C. fragilis is not driven by environmental factors, it could be facilitated by the perennial life-form of the species, its reproductive modes and efficient wind dispersal of spores. Independent origins of hexaploids and/or inter-ploidy gene flow may be expected in mixed-ploidy populations according to Cx value comparisons.
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Affiliation(s)
- Kristýna Hanušová
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek, Průhonice, Czech Republic
| | - Tomáš Urfus
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
| | - Petr Koutecký
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Jiří Košnar
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Carl J Rothfels
- University Herbarium and Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Vlasta Jarolímová
- Institute of Botany, The Czech Academy of Sciences, Zámek, Průhonice, Czech Republic
| | - Jan Ptáček
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
| | - Libor Ekrt
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
- For correspondence. E-mail
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Šingliarová B, Zozomová-Lihová J, Mráz P. Polytopic origin and scale-dependent spatial segregation of cytotypes in primary diploid–autopolyploid contact zones ofPilosella rhodopea(Asteraceae). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/bly199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Barbora Šingliarová
- Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta, Bratislava, Slovakia
| | - Judita Zozomová-Lihová
- Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta, Bratislava, Slovakia
| | - Patrik Mráz
- Herbarium and Department of Botany, Charles University, Benátská,Prague, Czech Republic
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Čertner M, Sudová R, Weiser M, Suda J, Kolář F. Ploidy-altered phenotype interacts with local environment and may enhance polyploid establishment in Knautia serpentinicola (Caprifoliaceae). THE NEW PHYTOLOGIST 2019; 221:1117-1127. [PMID: 30221362 DOI: 10.1111/nph.15426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Whole genome duplication is a key process in plant evolution and has direct phenotypic consequences. However, it remains unclear whether ploidy-related phenotypic changes can significantly alter the fitness of polyploids in nature and thus contribute to establishment of new polyploid mutants in diploid populations. We addressed this question using a unique natural system encompassing a diploid and its sympatric locally established autotetraploid derivative. By setting a common garden experiment with two manipulated environmental factors (presence/absence of serpentine substrate and competition), we tested whether these two locally important factors differently shape the phenotypic response of the two ploidy levels. Tetraploids attained significantly higher values of both above- and below-ground biomass, and root : shoot ratio compared to their diploid progenitors. Tetraploid superiority in vegetative fitness indicators was most prominent when they were cultivated together with a competitor in nutrient-rich nonserpentine substrate. We show that even genetically very closely related diploids and tetraploids can respond differently to key environmental factors. Provided there are sufficient nutrients, tetraploids can be more successful in tolerating interspecific competition than their diploid progenitors. Such superior performance might have provided an adaptive advantage for the newly established tetraploid promoting colonisation of new (micro-)habitats, which was indeed observed at the natural site.
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Affiliation(s)
- Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Radka Sudová
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Martin Weiser
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00, Prague, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
- Institute of Botany, University of Innsbruck, AT-6020, Innsbruck, Austria
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Molina-Henao YF, Hopkins R. Autopolyploid lineage shows climatic niche expansion but not divergence in Arabidopsis arenosa. AMERICAN JOURNAL OF BOTANY 2019; 106:61-70. [PMID: 30609009 DOI: 10.1002/ajb2.1212] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/24/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY Successful establishment of neopolyploids, and therefore polyploid speciation, is thought to be contingent on environmental niche shifts from their progenitors. We explore this niche shift hypothesis in the obligate outcrosser Arabidopsis arenosa complex, which includes diploid and recently formed autotetraploid populations. METHODS To characterize the climatic niches for both cytotypes in Arabidopsis arenosa, we first gathered climatic data from localities with known ploidy types. We then estimated the climatic niches for diploids and autotetraploids and calculated niche overlap. Using this niche overlap statistic, we tested for niche equivalency and similarity. We explored differences in niches by estimating and comparing niche optimum and breadth and then calculated indices of niche expansion and unfilling. KEY RESULTS Climatic niche overlap between diploids and autotetraploids is substantial. Although the two niche models are not significantly divergent, they are not identical as they differ in both optimum and breadth along two environmental gradients. Autotetraploids fill nearly the entire niche space of diploids and have expanded into novel environments. CONCLUSIONS We find climatic niche expansion but not divergence, together with a moderate change in the niche optimum, in the autotetraploid lineage of Arabidopsis arenosa. These results indicate that the climatic niche shift hypothesis alone cannot explain the coexistence of tetraploid and diploid cytotypes.
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Affiliation(s)
- Y Franchesco Molina-Henao
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- The Arnold Arboretum, Harvard University, Boston, MA, 02131, USA
- Departamento de Biología, Universidad del Valle, Cali, Valle, 760032, Colombia
| | - Robin Hopkins
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- The Arnold Arboretum, Harvard University, Boston, MA, 02131, USA
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Van Drunen WE, Husband BC. Whole-genome duplication decreases clonal stolon production and genet size in the wild strawberry Fragaria vesca. AMERICAN JOURNAL OF BOTANY 2018; 105:1712-1724. [PMID: 30248174 DOI: 10.1002/ajb2.1159] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 06/28/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Clonal reproduction is often associated with polyploidy and is expected to influence polyploid establishment success, but the immediate effects of whole-genome duplication (WGD) on clonal reproduction in autopolyploids are unknown. METHODS We used synthesized neopolyploids to assess the direct effects of WGD on stolon and plantlet production in the wild strawberry Fragaria vesca by (1) comparing absolute clonal investment between diploids and neotetraploids under high and low resource conditions in the greenhouse and (2) determining realized clonal plantlet establishment and genet spatial structure using artificial field populations comprising both cytotypes. KEY RESULTS Neotetraploids produced fewer stolons and plantlets than diploids at slower weekly rates in the greenhouse when resources were high, resulting in lower total investment in clonal reproduction. Low resources led to smaller reductions in clonal biomass for neotetraploids and less pronounced differences between cytotypes. Comparisons between neotetraploids representing 13 independent WGD events and close diploid relatives revealed considerable variation in the response to polyploidization for some clonal traits. Field populations corroborated greenhouse results; neotetraploid genets were smaller than diploid genets, containing 28% fewer stolons and 46% fewer rooted plantlets. CONCLUSIONS WGD significantly decreases the clonal output of neotetraploid F. vesca, which is likely attributable to slower whole-plant growth of the neotetraploids than the diploids. In natural populations, smaller neotetraploid genets could decrease the probability of polyploid establishment in this species. However, variation between separate neopolyploid lines emphasizes that the response of clonal investment to WGD may not be uniform across polyploid origins.
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Affiliation(s)
- Wendy E Van Drunen
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
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11
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Van Drunen WE, Husband BC. Immediate vs. evolutionary consequences of polyploidy on clonal reproduction in an autopolyploid plant. ANNALS OF BOTANY 2018; 122:195-205. [PMID: 29726889 PMCID: PMC6025202 DOI: 10.1093/aob/mcy071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/19/2018] [Indexed: 05/23/2023]
Abstract
Background and Aims Clonal reproduction in polyploids is expected to exceed that in diploids, due to either the immediate direct effects of whole-genome duplication (WGD) or selection during establishment. The timing of polyploidy effects on clonality are largely unknown despite its hypothesized influence on polyploid success. This study tests the direction and timing of divergence in clonal traits in diploid and polyploid Chamerion angustifolium. Methods Root bud production and biomass allocation patterns were compared between diploids and synthesized tetraploids (neotetraploids), and between neotetraploids and naturally occurring tetraploids grown in a common environment. Key Results Neotetraploids produced more root buds and fewer sexual structures than diploids and natural tetraploids; diploids and natural tetraploids had similar root bud numbers and sexual investment. The root bud:inflorescence biomass ratio was 71 % higher in neotetraploids than in natural tetraploids. Root bud location suggests that ramet density in neotetraploid genets could be higher than in diploid genets. Conclusions WGD immediately increases investment in asexual vs. sexual reproduction in C. angustifolium, potentially promoting within-cytotype mating and establishment for neopolyploids. However, evolutionary change after the polyploidization event negates the direct effects of WGD. Natural polyploids and diploids have similar root bud production and biomass allocation patterns, probably resulting from habitat- and ploidy-mediated selection on polyploids to become more like diploids. These results highlight the value of studying the effects of polyploidization in young vs. established polyploids.
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Affiliation(s)
- Wendy E Van Drunen
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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Kolář F, Čertner M, Suda J, Schönswetter P, Husband BC. Mixed-Ploidy Species: Progress and Opportunities in Polyploid Research. TRENDS IN PLANT SCIENCE 2017; 22:1041-1055. [PMID: 29054346 DOI: 10.1016/j.tplants.2017.09.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/12/2017] [Accepted: 09/18/2017] [Indexed: 05/07/2023]
Abstract
Mixed-ploidy species harbor a unique form of genomic and phenotypic variation that influences ecological interactions, facilitates genetic divergence, and offers insights into the mechanisms of polyploid evolution. However, there have been few attempts to synthesize this literature. We review here research on the cytotype distribution, diversity, and dynamics of intensively studied mixed-ploidy species and consider the implications for understanding mechanisms of polyploidization such as cytotype formation, establishment, coexistence, and post-polyploid divergence. In general, mixed-ploidy species are unevenly represented among families: they exhibit high cytotype diversity, often within populations, and frequently comprise rare and odd-numbered ploidies. Odd-ploidies often occur in association with asexuality. We highlight research hypotheses and opportunities that take advantage of the unique properties of ploidy variation.
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Affiliation(s)
- Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, Praha, CZ-128 00, Czech Republic; Institute of Botany, The Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, Praha, CZ-128 00, Czech Republic; Institute of Botany, The Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University, Benátská 2, Praha, CZ-128 00, Czech Republic; Institute of Botany, The Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
| | - Peter Schönswetter
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, ON, N0B 2K0 Canada.
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Čertner M, Fenclová E, Kúr P, Kolář F, Koutecký P, Krahulcová A, Suda J. Evolutionary dynamics of mixed-ploidy populations in an annual herb: dispersal, local persistence and recurrent origins of polyploids. ANNALS OF BOTANY 2017; 120:303-315. [PMID: 28398545 PMCID: PMC5737363 DOI: 10.1093/aob/mcx032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/08/2017] [Indexed: 05/18/2023]
Abstract
Background and Aims Despite the recent wealth of studies targeted at contact zones of cytotypes in various species, some aspects of polyploid evolution are still poorly understood. This is especially the case for the frequency and success rate of spontaneous neopolyploidization or the temporal dynamics of ploidy coexistence, requiring massive ploidy screening and repeated observations, respectively. To fill this gap, an extensive study of spatio-temporal patterns of ploidy coexistence was initiated in the widespread annual weed Tripleurospermum inodorum (Asteraceae). Methods DNA flow cytometry along with confirmatory chromosome counts was employed to assess ploidy levels of 11 018 adult individuals and 1263 ex situ germinated seedlings from 1209 Central European populations. The ploidy screening was conducted across three spatial scales and supplemented with observations of temporal development of 37 mixed-ploidy populations. Key Results The contact zone between the diploid and tetraploid cytotypes has a diffuse, mosaic-like structure enabling common cytotype coexistence from the within-population to the landscape level. A marked difference in monoploid genome size between the two cytotypes enabled the easy distinction of neotetraploid mutants from long-established tetraploids. Neotetraploids were extremely rare (0·03 %) and occurred solitarily. Altogether five ploidy levels (2 x -6 x ) and several aneuploids were discovered; the diversity in nuclear DNA content was highest in early ontogenetic stages (seedlings) and among individuals from mixed-ploidy populations. In spite of profound temporal oscillations in cytotype frequencies in mixed-ploidy populations, both diploids and tetraploids usually persisted up to the last census. Conclusions Diploids and tetraploids commonly coexist at all spatial scales and exhibit considerable temporal stability in local ploidy mixtures. Mixed-ploidy populations containing fertile triploid hybrids probaby act as effective generators of cytogenetic novelty and may facilitate inter-ploidy gene flow. Neopolyploid mutants were incapable of local establishment.
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Affiliation(s)
- Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Eliška Fenclová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
| | - Pavel Kúr
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-370 05 České Budějovice, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
- National Centre for Biosystematics, Natural History Museum, University of Oslo, NO-0318 Oslo, Norway
| | - Petr Koutecký
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-370 05 České Budějovice, Czech Republic
| | - Anna Krahulcová
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
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Eliášová A, Münzbergová Z. Factors influencing distribution and local coexistence of diploids and tetraploids of Vicia cracca: inferences from a common garden experiment. JOURNAL OF PLANT RESEARCH 2017; 130:677-687. [PMID: 28290078 DOI: 10.1007/s10265-017-0925-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 01/24/2017] [Indexed: 06/06/2023]
Abstract
Vicia cracca diploids and autotetraploids are highly parapatric in Europe; tetraploids reside in western and northern part, whereas diploids occupy much drier south-eastern part. They meet together in a Central European contact zone. This distribution pattern raised questions about a transformative effect of polyploidization on plant performance and environmental tolerances. We investigated plant survival, growth, and seed production in two water regimes in a common garden experiment using seeds collected from five localities in the Central European contact zone where diploids and tetraploids occur in sympatry. Obtained data imply that tetraploids of V. cracca are not generally superior in performance to diploids. Significantly larger seeds from tetraploid mother plants collected in the field were not correlated with greater stature of the seedlings. Nonetheless, tetraploids might have a potential to out-compete diploids in the long run due to the tetraploids' ability of greater growth which manifested in the second year of cultivation. Considering the response of diploids and tetraploids to water supply, drought stressed tetraploids but not diploids produced a higher proportion of aborted seeds than watered ones, which implies that tetraploids are more drought susceptible than diploids. On the other hand, decreased plant height in drought stresses tetraploids, which simultaneously increased total seed production, may suggest that tetraploids have a greater ability to avoid local extinction under unfavourable conditions by enhancing biomass allocation into production of seeds at the cost of lower growth. The significant interaction between ploidy level and locality in several traits suggests possible polyfyletic origin of tetraploids and the necessity to clarify the history of the tetraploids in Europe.
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Affiliation(s)
- Anežka Eliášová
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01, Prague, Czech Republic.
| | - Zuzana Münzbergová
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01, Prague, Czech Republic.
- Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, 252 43, Průhonice, Czech Republic.
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Weber MG, Strauss SY. Coexistence in Close Relatives: Beyond Competition and Reproductive Isolation in Sister Taxa. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2016. [DOI: 10.1146/annurev-ecolsys-112414-054048] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marjorie G. Weber
- Center for Population Biology, University of California, Davis, California 95616; ,
| | - Sharon Y. Strauss
- Center for Population Biology, University of California, Davis, California 95616; ,
- Department of Evolution and Ecology, University of California, Davis, California 95616
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Frajman B, Rešetnik I, Niketić M, Ehrendorfer F, Schönswetter P. Patterns of rapid diversification in heteroploid Knautia sect. Trichera (Caprifoliaceae, Dipsacoideae), one of the most intricate taxa of the European flora. BMC Evol Biol 2016; 16:204. [PMID: 27724874 PMCID: PMC5057222 DOI: 10.1186/s12862-016-0773-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 09/28/2016] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Polyploidy is one of the most important evolutionary pathways in flowering plants and has significantly contributed to their diversification and radiation. Due to the prevalence of reticulate evolution spanning three ploidy levels, Knautia is considered one of the taxonomically most intricate groups in the European flora. On the basis of ITS and plastid DNA sequences as well as AFLP fingerprints obtained from 381 populations of almost all species of the genus we asked the following questions. (1) Where and when did the initial diversification in Knautia take place, and how did it proceed further? (2) Did Knautia undergo a similarly recent (Pliocene/Pleistocene) rapid radiation as other genera with similar ecology and overlapping distribution? (3) Did polyploids evolve within the previously recognised diploid groups or rather from hybridisation between groups? RESULTS The diversification of Knautia was centred in the Eastern Mediterranean. According to our genetic data, the genus originated in the Early Miocene and started to diversify in the Middle Miocene, whereas the onset of radiation of sect. Trichera was in central parts of the Balkan Peninsula, roughly 4 Ma. Extensive spread out of the Balkans started in the Pleistocene about 1.5 Ma. Diversification of sect. Trichera was strongly fostered by polyploidisation, which occurred independently many times. Tetraploids are observed in almost all evolutionary lineages whereas hexaploids are rarer and restricted to a few phylogenetic groups. Whether polyploids originated via autopolyploidy or allopolyploidy is unclear due to the weak genetic separation among species. In spite of the complexity of sect. Trichera, we present nine AFLP-characterised informal species groups, which coincide only partly with former traditional groups. CONCLUSIONS Knautia sect. Trichera is a prime example for rapid diversification, mostly taking place during Pliocene and Pleistocene. Numerous cycles of habitat fragmentation and subsequent reconnections likely promoted hybridisation and polyploidisation. Extensive haplotype sharing and unresolved phylogenetic relationships suggest that these processes occurred rapidly and extensively. Thus, the dynamic polyploid evolution, the lack of crossing barriers within ploidy levels supported by conserved floral morphology, the highly variable leaf morphology and unstable indumentum composition prevent establishing a well-founded taxonomic framework.
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Affiliation(s)
- Božo Frajman
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria
| | - Ivana Rešetnik
- Faculty of Science, University of Zagreb, Marulićev trg 20, HR-10000 Zagreb, Croatia
| | - Marjan Niketić
- Natural History Museum, Njegoševa 51, 11000 Belgrade, Serbia
| | - Friedrich Ehrendorfer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
| | - Peter Schönswetter
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria
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Čertner M, Kolář F, Schönswetter P, Frajman B. Does hybridization with a widespread congener threaten the long-term persistence of the Eastern Alpine rare local endemic Knautia carinthiaca? Ecol Evol 2015; 5:4263-76. [PMID: 26664677 PMCID: PMC4667829 DOI: 10.1002/ece3.1686] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/31/2015] [Accepted: 08/05/2015] [Indexed: 12/22/2022] Open
Abstract
Interspecific hybridization, especially when regularly followed by backcrossing (i.e., introgressive hybridization), conveys a substantial risk for many endangered organisms. This is particularly true for narrow endemics occurring within distributional ranges of widespread congeners. An excellent example is provided by the plant genus Knautia (Caprifoliaceae): Locally endemic K. carinthiaca is reported from two isolated populations in southern Austria situated within an area predominantly occupied by widespread K. arvensis. While K. carinthiaca usually inhabits low-competition communities on rocky outcrops, K. arvensis occurs mainly in dry to mesic managed grasslands, yet both species can coexist in marginal environments and were suspected to hybridize. Flow cytometry revealed that diploid K. carinthiaca only occurs at its locus classicus, whereas the second locality is inhabited by the morphologically similar but tetraploid K. norica. In the, therefore, single population of K. carinthiaca, flow cytometry and AFLP fingerprinting showed signs of introgressive hybridization with diploid K. arvensis. Hybridization patterns were also reflected in intermediate habitat preferences and morphology of the hybrids. Environmental barriers to gene flow seem to prevent genetic erosion of K. carinthiaca individuals from the core ecological niches, restricting most introgressed individuals to peripheral habitats. Efficient conservation of K. carinthiaca will require strict protection of its habitat and ban on forest clear cuts in a buffer zone to prevent invasion of K. arvensis. We demonstrate the large potential of multidisciplinary approaches combining molecular, cytometric, and ecological tools for a reliable inventory and threat assessment of rare species.
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Affiliation(s)
- Martin Čertner
- Department of BotanyFaculty of ScienceCharles University in PragueBenátská 2CZ‐128 00PragueCzech Republic
- Institute of BotanyThe Czech Academy of SciencesZámek 1CZ‐252 43PrůhoniceCzech Republic
| | - Filip Kolář
- Department of BotanyFaculty of ScienceCharles University in PragueBenátská 2CZ‐128 00PragueCzech Republic
- Institute of BotanyThe Czech Academy of SciencesZámek 1CZ‐252 43PrůhoniceCzech Republic
- National Centre for BiosystematicsNatural History MuseumUniversity of OsloNO‐0318OsloNorway
| | - Peter Schönswetter
- Institute of BotanyUniversity of InnsbruckSternwartestraße 156020InnsbruckAustria
| | - Božo Frajman
- Institute of BotanyUniversity of InnsbruckSternwartestraße 156020InnsbruckAustria
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Zozomová-Lihová J, Malánová-Krásná I, Vít P, Urfus T, Senko D, Svitok M, Kempa M, Marhold K. Cytotype distribution patterns, ecological differentiation, and genetic structure in a diploid-tetraploid contact zone of Cardamine amara. AMERICAN JOURNAL OF BOTANY 2015; 102:1380-95. [PMID: 26290560 DOI: 10.3732/ajb.1500052] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 07/16/2015] [Indexed: 05/20/2023]
Abstract
UNLABELLED • PREMISE OF THE STUDY Contact zones between diploids and their autopolyploid descendants represent a unique evolutionary venue for studying polyploid establishment, cytotype coexistence, and interactions. Here, we examine cytotype coexistence in a diploid-tetraploid contact zone of a perennial herb, Cardamine amara, located north of the Alps by assessing cytotype spatial patterns, ecological divergence, and genetic variation and structure.• METHODS Flow cytometry was applied to screen DNA ploidy levels in 302 populations (3296 individuals) and the genetic variation of a selection of 25 populations was examined using microsatellite and AFLP markers. Environmental (landscape and climatic) data were analyzed to assess ecological differentiation between the cytotypes.• KEY RESULTS A parapatric distribution of the cytotypes with a relatively wide (over 100 km in some regions) secondary contact zone was identified. Mixed-ploidy populations, documented for the first time in this species, as well as triploid individuals were found along the diploid-tetraploid borderline. Different climatic requirements of the two main cytotypes were revealed, mirrored in their altitudinal separation. The tetraploids were genetically differentiated from both the diploids and the modeled, in silico autotetraploid genotypes, in accordance with the assumed polyploid origin and spread linked to past glaciations, and largely independent evolution in allopatry.• CONCLUSIONS The observed spatial and genetic patterns likely reflect the evolutionary and colonization history of the two cytotypes and have been maintained by multiple factors such as ecological divergence, limited gene flow between the cytotypes, and the restricted dispersal capacity.
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Affiliation(s)
- Judita Zozomová-Lihová
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic
| | | | - Petr Vít
- Department of Botany, Faculty of Sciences, Charles University, Benátská 2, CZ-128 01 Praha, Czech Republic Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Tomáš Urfus
- Department of Botany, Faculty of Sciences, Charles University, Benátská 2, CZ-128 01 Praha, Czech Republic Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Dušan Senko
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic
| | - Marek Svitok
- Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, T. G. Masaryka 24, SK-960 53 Zvolen, Slovak Republic Eawag Swiss Federal Institute of Aquatic Science and Technology, Department of Aquatic Ecology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland
| | - Matúš Kempa
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic
| | - Karol Marhold
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic Department of Botany, Faculty of Sciences, Charles University, Benátská 2, CZ-128 01 Praha, Czech Republic
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Hülber K, Sonnleitner M, Suda J, Krejčíková J, Schönswetter P, Schneeweiss GM, Winkler M. Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae). Ecol Evol 2015; 5:1224-34. [PMID: 25859328 PMCID: PMC4377266 DOI: 10.1002/ece3.1430] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 11/09/2022] Open
Abstract
Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, that is, the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering, and ecological niches as well as patterns of gene flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra-, and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated microscale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids.
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Affiliation(s)
- Karl Hülber
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
- Vienna Institute for Nature Conservation & AnalysesVienna, Austria
| | - Michaela Sonnleitner
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in PraguePrague, Czech Republic
- Institute of Botany, The Czech Academy of SciencesPrůhonice, Czech Republic
| | - Jana Krejčíková
- Department of Botany, Faculty of Science, Charles University in PraguePrague, Czech Republic
| | | | - Gerald M Schneeweiss
- Division of Systematics and Evolutionary Botany, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
| | - Manuela Winkler
- Division of Systematics and Evolutionary Botany, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
- GLORIA co-ordination, Center for Global Change and Sustainability, University of Natural Resources and Life Sciences ViennaVienna, Austria
- Institute for Interdisciplinary Mountain Research, Austrian Academy of SciencesInnsbruck, Austria
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