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Abdelaziz M, Muñoz-Pajares AJ, Berbel M, García-Muñoz A, Gómez JM, Perfectti F. Asymmetric Reproductive Barriers and Gene Flow Promote the Rise of a Stable Hybrid Zone in the Mediterranean High Mountain. FRONTIERS IN PLANT SCIENCE 2021; 12:687094. [PMID: 34512685 PMCID: PMC8424041 DOI: 10.3389/fpls.2021.687094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 07/15/2021] [Indexed: 05/13/2023]
Abstract
Hybrid zones have the potential to shed light on evolutionary processes driving adaptation and speciation. Secondary contact hybrid zones are particularly powerful natural systems for studying the interaction between divergent genomes to understand the mode and rate at which reproductive isolation accumulates during speciation. We have studied a total of 720 plants belonging to five populations from two Erysimum (Brassicaceae) species presenting a contact zone in the Sierra Nevada mountains (SE Spain). The plants were phenotyped in 2007 and 2017, and most of them were genotyped the first year using 10 microsatellite markers. Plants coming from natural populations were grown in a common garden to evaluate the reproductive barriers between both species by means of controlled crosses. All the plants used for the field and greenhouse study were characterized by measuring traits related to plant size and flower size. We estimated the genetic molecular variances, the genetic differentiation, and the genetic structure by means of the F-statistic and Bayesian inference. We also estimated the amount of recent gene flow between populations. We found a narrow unimodal hybrid zone where the hybrid genotypes appear to have been maintained by significant levels of a unidirectional gene flow coming from parental populations and from weak reproductive isolation between them. Hybrid plants exhibited intermediate or vigorous phenotypes depending on the analyzed trait. The phenotypic differences between the hybrid and the parental plants were highly coherent between the field and controlled cross experiments and through time. The highly coherent results obtained by combining field, experimental, and genetic data demonstrate the existence of a stable and narrow unimodal hybrid zone between Erysimum mediohispanicum and Erysimum nevadense at the high elevation of the Sierra Nevada mountains.
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Affiliation(s)
- Mohamed Abdelaziz
- Departamento de Genética, Facultad de Ciencias, Campus Fuentenueva, Universidad de Granada, Granada, Spain
- *Correspondence: Mohamed Abdelaziz
| | - A. Jesús Muñoz-Pajares
- Departamento de Genética, Facultad de Ciencias, Campus Fuentenueva, Universidad de Granada, Granada, Spain
- Laboratório Associado, Plant Biology, Research Centre in Biodiversity and Genetic Resources, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade Do Porto, Campus Agrário de Vairão, Fornelo e Vairão, Portugal
- Research Unit Modeling Nature, Universidad de Granada, Granada, Spain
| | - Modesto Berbel
- Departamento de Genética, Facultad de Ciencias, Campus Fuentenueva, Universidad de Granada, Granada, Spain
| | - Ana García-Muñoz
- Departamento de Genética, Facultad de Ciencias, Campus Fuentenueva, Universidad de Granada, Granada, Spain
| | - José M. Gómez
- Research Unit Modeling Nature, Universidad de Granada, Granada, Spain
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Almeria, Spain
| | - Francisco Perfectti
- Departamento de Genética, Facultad de Ciencias, Campus Fuentenueva, Universidad de Granada, Granada, Spain
- Research Unit Modeling Nature, Universidad de Granada, Granada, Spain
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Chaplin K, Sumner J, Hipsley CA, Melville J. An Integrative Approach Using Phylogenomics and High-Resolution X-Ray Computed Tomography for Species Delimitation in Cryptic Taxa. Syst Biol 2020; 69:294-307. [PMID: 31372642 DOI: 10.1093/sysbio/syz048] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/18/2019] [Accepted: 07/12/2019] [Indexed: 11/14/2022] Open
Abstract
Morphologically cryptic taxa have proved to be a long-standing challenge for taxonomists. Lineages that show strong genomic structuring across the landscape but are phenotypically similar pose a conundrum, with traditional morphological analyses of these cryptic lineages struggling to keep up with species delimitation advances. Micro X-ray computed tomography (CT) combined with geometric morphometric analyses provides a promising avenue for identification of morphologically cryptic taxa, given its ability to detect subtle differences in anatomical structures. However, this approach has yet to be used in combination with genomic data in a comparative analytical framework to distinguish cryptic taxa. We present an integrative approach incorporating genomic and geometric morphometric evidence to assess the species delimitation of grassland earless dragons (Tympanocryptis spp.) in north-eastern Australia. Using mitochondrial and nuclear genes (ND2 and RAG1, respectively), along with $>$8500 SNPs (nuclear single nucleotide polymorphisms), we assess the evolutionary independence of target lineages and several closely related species. We then integrate phylogenomic data with osteological cranial variation between lineages using landmark-based analyses of three-dimensional CT models. High levels of genomic differentiation between the three target lineages were uncovered, also supported by significant osteological differences. By incorporating multiple lines of evidence, we provide strong support for three undescribed cryptic lineages of Tympanocryptis in north-eastern Australia that warrant taxonomic review. Our approach demonstrates the successful application of CT with integrative taxonomic approaches for cryptic species delimitation, which is broadly applicable across vertebrates containing morphologically similar yet genetically distinct lineages. Additionally, we provide a review of recent integrative taxonomic approaches for cryptic species delimitation and an assessment of how our approach can value-add to taxonomic research.
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Affiliation(s)
- Kirilee Chaplin
- Department of Sciences, Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia.,School of BioSciences The University of Melbourne Parkville Campus Victoria 3010, Australia
| | - Joanna Sumner
- Department of Sciences, Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia
| | - Christy A Hipsley
- Department of Sciences, Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia.,School of BioSciences The University of Melbourne Parkville Campus Victoria 3010, Australia
| | - Jane Melville
- Department of Sciences, Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia
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Züst T, Strickler SR, Powell AF, Mabry ME, An H, Mirzaei M, York T, Holland CK, Kumar P, Erb M, Petschenka G, Gómez JM, Perfectti F, Müller C, Pires JC, Mueller LA, Jander G. Independent evolution of ancestral and novel defenses in a genus of toxic plants ( Erysimum, Brassicaceae). eLife 2020; 9:51712. [PMID: 32252891 PMCID: PMC7180059 DOI: 10.7554/elife.51712] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 03/24/2020] [Indexed: 11/13/2022] Open
Abstract
Phytochemical diversity is thought to result from coevolutionary cycles as specialization in herbivores imposes diversifying selection on plant chemical defenses. Plants in the speciose genus Erysimum (Brassicaceae) produce both ancestral glucosinolates and evolutionarily novel cardenolides as defenses. Here we test macroevolutionary hypotheses on co-expression, co-regulation, and diversification of these potentially redundant defenses across this genus. We sequenced and assembled the genome of E. cheiranthoides and foliar transcriptomes of 47 additional Erysimum species to construct a phylogeny from 9868 orthologous genes, revealing several geographic clades but also high levels of gene discordance. Concentrations, inducibility, and diversity of the two defenses varied independently among species, with no evidence for trade-offs. Closely related, geographically co-occurring species shared similar cardenolide traits, but not glucosinolate traits, likely as a result of specific selective pressures acting on each defense. Ancestral and novel chemical defenses in Erysimum thus appear to provide complementary rather than redundant functions. Plants are often attacked by insects and other herbivores. As a result, they have evolved to defend themselves by producing many different chemicals that are toxic to these pests. As producing each chemical costs energy, individual plants often only produce one type of chemical that is targeted towards their main herbivore. Related species of plants often use the same type of chemical defense so, if a particular herbivore gains the ability to cope with this chemical, it may rapidly become an important pest for the whole plant family. To escape this threat, some plants have gained the ability to produce more than one type of chemical defense. Wallflowers, for example, are a group of plants in the mustard family that produce two types of toxic chemicals: mustard oils, which are common in most plants in this family; and cardenolides, which are an innovation of the wallflowers, and which are otherwise found only in distantly related plants such as foxglove and milkweed. The combination of these two chemical defenses within the same plant may have allowed the wallflowers to escape attacks from their main herbivores and may explain why the number of wallflower species rapidly increased within the last two million years. Züst et al. have now studied the diversity of mustard oils and cardenolides present in many different species of wallflower. This analysis revealed that almost all of the tested wallflower species produced high amounts of both chemical defenses, while only one species lacked the ability to produce cardenolides. The levels of mustard oils had no relation to the levels of cardenolides in the tested species, which suggests that the regulation of these two defenses is not linked. Furthermore, Züst et al. found that closely related wallflower species produced more similar cardenolides, but less similar mustard oils, to each other. This suggests that mustard oils and cardenolides have evolved independently in wallflowers and have distinct roles in the defense against different herbivores. The evolution of insect resistance to pesticides and other toxins is an important concern for agriculture. Applying multiple toxins to crops at the same time is an important strategy to slow the evolution of resistance in the pests. The findings of Züst et al. describe a system in which plants have naturally evolved an equivalent strategy to escape their main herbivores. Understanding how plants produce multiple chemical defenses, and the costs involved, may help efforts to breed crop species that are more resistant to herbivores and require fewer applications of pesticides.
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Affiliation(s)
- Tobias Züst
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | | | | | - Makenzie E Mabry
- Division of Biological Sciences, University of Missouri, Columbia, United States
| | - Hong An
- Division of Biological Sciences, University of Missouri, Columbia, United States
| | | | - Thomas York
- Boyce Thompson Institute, Ithaca, United States
| | | | - Pavan Kumar
- Boyce Thompson Institute, Ithaca, United States
| | - Matthias Erb
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Georg Petschenka
- Institut für Insektenbiotechnologie, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - José-María Gómez
- Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas (EEZA-CSIC), Almería, Spain
| | - Francisco Perfectti
- Research Unit Modeling Nature, Department of Genetics, University of Granada, Granada, Spain
| | - Caroline Müller
- Department of Chemical Ecology, Bielefeld University, Bielefeld, Germany
| | - J Chris Pires
- Division of Biological Sciences, University of Missouri, Columbia, United States
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Inter-annual maintenance of the fine-scale genetic structure in a biennial plant. Sci Rep 2016; 6:37712. [PMID: 27883087 PMCID: PMC5121606 DOI: 10.1038/srep37712] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/02/2016] [Indexed: 11/13/2022] Open
Abstract
Within plant populations, space-restricted gene movement, together with environmental heterogeneity, can result in a spatial variation in gene frequencies. In biennial plants, inter-annual flowering migrants can homogenize gene frequencies between consecutive cohorts. However, the actual impact of these migrants on spatial genetic variation remains unexplored. Here, we used 10 nuclear microsatellite and one plastid genetic marker to characterize the spatial genetic structure within two consecutive cohorts in a population of the biennial plant Erysimum mediohispanicum (Brassicaceae). We explored the maintenance of this structure between consecutive flowering cohorts at different levels of complexity, and investigated landscape effects on gene flow. We found that cohorts were not genetically differentiated and showed a spatial genetic structure defined by a negative genetic-spatial correlation at fine scale that varied in intensity with compass directions. This spatial genetic structure was maintained when comparing plants from different cohorts. Additionally, genotypes were consistently associated with environmental factors such as light availability and soil composition, but to a lesser extent compared with the spatial autocorrelation. We conclude that inter-annual migrants, in combination with limited seed dispersal and environmental heterogeneity, play a major role in shaping and maintaining the spatial genetic structure among cohorts in this biennial plant.
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Boltenkov EV, Artyukova EV, Kozyrenko MM. Species divergence in Iris series Lacteae (Iridaceae) in Russia and adjacent countries based on chloroplast DNA sequence data. RUSS J GENET+ 2016. [DOI: 10.1134/s1022795416040037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gómez JM, Perfectti F, Lorite J. The role of pollinators in floral diversification in a clade of generalist flowers. Evolution 2015; 69:863-78. [PMID: 25757195 DOI: 10.1111/evo.12632] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/26/2015] [Indexed: 11/30/2022]
Abstract
Pollinator-mediated evolutionary divergence has seldom been explored in generalist clades because it is assumed that pollinators in those clades exert weak and conflicting selection. We investigate whether pollinators shape floral diversification in a pollination generalist plant genus, Erysimum. Species from this genus have flowers that appeal to broad assemblages of pollinators. Nevertheless, we recently reported that it is possible to sort plant species into pollination niches varying in the quantitative composition of pollinators. We test here whether floral characters of Erysimum have evolved as a consequence of shifts among pollination niches. For this, we quantified the evolutionary lability of the floral traits and their phylogenetic association with pollination niches. As with pollination niches, Erysimum floral traits show weak phylogenetic signal. Moreover, floral shape and color are phylogenetically associated with pollination niche. In particular, plants belonging to a pollination niche dominated by long-tongued large bees have lilac corollas with parallel petals. Further analyses suggest, however, that changes in color preceded changes in pollination niche. Pollinators seem to have driven the evolution of corolla shape, whereas the association between pollination niche and corolla color has probably arisen by lilac-flowered Erysimum moving toward certain pollination niches for other adaptive reasons.
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Affiliation(s)
- José M Gómez
- Dpto de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Aridas (EEZA-CSIC), E-04120, Almería, Spain; Dpto de Ecología, Universidad de Granada, E-18071, Granada, Spain.
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Barata M, Perera A, Harris DJ. Cryptic variation in the Moroccan high altitude lizardAtlantolacerta andreanskyi(Squamata: Lacertidae). AFR J HERPETOL 2015. [DOI: 10.1080/21564574.2014.967815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Gómez JM, Perfectti F, Abdelaziz M, Lorite J, Muñoz-Pajares AJ, Valverde J. Evolution of pollination niches in a generalist plant clade. THE NEW PHYTOLOGIST 2015; 205:440-53. [PMID: 25252267 DOI: 10.1111/nph.13016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 07/29/2014] [Indexed: 05/27/2023]
Abstract
It is widely assumed that floral diversification occurs by adaptive shifts between pollination niches. In contrast to specialized flowers, identifying pollination niches of generalist flowers is a challenge. Consequently, how generalist pollination niches evolve is largely unknown. We apply tools from network theory and comparative methods to investigate the evolution of pollination niches among generalist species belonging to the genus Erysimum. These species have similar flowers. We found that the studied species may be grouped in several multidimensional niches separated not by a shift of pollinators, but instead by quantitative variation in the relative abundance of pollinator functional groups. These pollination niches did not vary in generalization degree; we did not find any evolutionary trend toward specialization within the studied clade. Furthermore, the evolution of pollination niche fitted to a Brownian motion model without phylogenetic signal, and was characterized by frequent events of niche convergences and divergences. We presume that the evolution of Erysimum pollination niches has occurred mostly by recurrent shifts between slightly different generalized pollinator assemblages varying spatially as a mosaic and without any change in specialization degree. Most changes in pollination niches do not prompt floral divergence, a reason why adaptation to pollinators is uncommon in generalist plants.
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Affiliation(s)
- José María Gómez
- Dpto de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Aridas (EEZA-CSIC), E-04120, Almería, Spain; Dpto de Ecología, Universidad de Granada, E-18071, Granada, Spain
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9
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Abdelaziz M, Muñoz-Pajares AJ, Berbel M, Perfectti F, Gómez JM. Association between inbreeding depression and floral traits in a generalist-pollinated plant. J Evol Biol 2014; 27:2495-506. [DOI: 10.1111/jeb.12492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 08/10/2014] [Accepted: 09/01/2014] [Indexed: 11/28/2022]
Affiliation(s)
- M. Abdelaziz
- Biological and Environmental Sciences; School of Natural Sciences; University of Stirling; Stirling UK
- Departamento de Genética; Universidad de Granada; Granada Spain
| | - A. J. Muñoz-Pajares
- Departamento de Genética; Universidad de Granada; Granada Spain
- Centro de Investigação em Biodiversidade e Recursos Genéticos; CIBIO; Vairão Portugal
| | - M. Berbel
- Departamento de Ecología; Universidad de Granada; Granada Spain
| | - F. Perfectti
- Departamento de Genética; Universidad de Granada; Granada Spain
| | - J. M. Gómez
- Departamento de Ecología; Universidad de Granada; Granada Spain
- Departamento de Ecología Funcional y Evolutiva; Estación Experimental de Zonas Aridas (EEZA-CSIC); Almería Spain
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10
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Through thick and thin: cryptic sympatric speciation in the submersed genus Najas (Hydrocharitaceae). Mol Phylogenet Evol 2014; 82 Pt A:15-30. [PMID: 25300454 DOI: 10.1016/j.ympev.2014.09.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 09/12/2014] [Accepted: 09/22/2014] [Indexed: 11/22/2022]
Abstract
Cryptic sympatric species arise when reproductive isolation is established in sympatry, leading to genetically divergent lineages that are highly similar morphologically or virtually indistinguishable. Although cryptic sympatric species have been reported in various animals, fungi, and protists, there are few compelling examples for plants. This investigation presents a case for cryptic sympatric speciation in Najas flexilis, a widespread aquatic plant, which extends throughout northern North America and Eurasia. The taxon is noted for its variable seed morphology, which earlier research associated with cytotypes; i.e., diploids were characterized by thicker seeds and tetraploids by thinner seeds. However, cytotypes are not patterned geographically with diploid and tetraploid plants often found in close proximity within the same lake. Using digital image and DNA sequence analyses, we found that diploids and tetraploids are well-isolated and remain genetically distinct throughout their sympatric range, where sterile hybrids occur frequently. Incorporation of sequence data from the single-copy nuclear phytoene desaturase locus revealed further that the tetraploids are allopolyploid derivatives of N. flexilis and N. guadalupensis, the latter a closely related species with an overlapping distribution. We conclude that the taxon widely known as N. flexilis actually comprises two cryptic, sibling species, which diverged in sympatry by interspecific hybridization and subsequent chromosomal isolation. By comparing seed morphology of type specimens, we associated the names N. flexilis and N. canadensis to the diploids and tetraploids respectively. Additionally, the narrowly restricted taxon known formerly as N. muenscheri is shown via morphological and genetic evidence to be synonymous with N. canadensis.
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Gómez JM, Perfectti F, Klingenberg CP. The role of pollinator diversity in the evolution of corolla-shape integration in a pollination-generalist plant clade. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130257. [PMID: 25002702 PMCID: PMC4084542 DOI: 10.1098/rstb.2013.0257] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Flowers of animal-pollinated plants are integrated structures shaped by the action of pollinator-mediated selection. It is widely assumed that pollination specialization increases the magnitude of floral integration. However, empirical evidence is still inconclusive. In this study, we explored the role of pollinator diversity in shaping the evolution of corolla-shape integration in Erysimum, a plant genus with generalized pollination systems. We quantified floral integration in Erysimum using geometric morphometrics and explored its evolution using phylogenetic comparative methods. Corolla-shape integration was low but significantly different from zero in all study species. Spatial autocorrelation and phylogenetic signal in corolla-shape integration were not detected. In addition, integration in Erysimum seems to have evolved in a way that is consistent with Brownian motion, but with frequent convergent evolution. Corolla-shape integration was negatively associated with the number of pollinators visiting the flowers of each Erysimum species. That is, it was lower in those species having a more generalized pollination system. This negative association may occur because the co-occurrence of many pollinators imposes conflicting selection and cancels out any consistent selection on specific floral traits, preventing the evolution of highly integrated flowers.
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Affiliation(s)
- José María Gómez
- Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas (EEZA-CSIC), University of Granada, Granada, Spain Department of Ecology, University of Granada, Granada, Spain
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12
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One or three species in Megadenia (Brassicaceae): insight from molecular studies. Genetica 2014; 142:337-50. [PMID: 25027851 DOI: 10.1007/s10709-014-9778-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 07/09/2014] [Indexed: 10/25/2022]
Abstract
Megadenia Maxim. is a small genus of the Brassicaceae endemic to East Asia with three disjunct areas of distribution: the eastern edge of the Qinghai-Tibetan Plateau, the Eastern Sayan Mountains in southern Siberia, and Chandalaz Ridge in the southern Sikhote-Alin Mountains. Although distinct species (M. pygmaea Maxim., M. bardunovii Popov, and M. speluncarum Vorob., Vorosch. and Gorovoj) have been described from each area, they have lately been reduced to synonymy with M. pygmaea due to high morphological similarity. Here, we present the first molecular study of Megadenia. Using the sequences of 11 noncoding regions from the cytoplasmic (chloroplast and mitochondrial) and nuclear genomes, we assessed divergence within the genus and explored the relationships between Megadenia and Biscutella L. Although M. bardunovii, M. speluncarum, and M. pygmaea were found to be indiscernible with regard to the nuclear and mitochondrial markers studied, our data on the plastid genome revealed their distinctness and a clear subdivision of the genus into three lineages matching the three described species. All of the phylogenetic analyses of the chloroplast DNA sequences provide strong support for the inclusion of Megadenia and Biscutella in the tribe Biscutelleae. A dating analysis shows that the genus Megadenia is of Miocene origin and diversification within the genus, which has led to the three extant lineages, most likely occurred during the Early-Middle Pleistocene, in agreement with the vicariance pattern. Given the present-day distribution, differences in habitat preferences and in some anatomical traits, and lack of a direct genealogical relationship, M. pygmaea, M. bardunovii, and M. speluncarum should be treated as distinct species or at least subspecies.
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Fernández-Mazuecos M, Blanco-Pastor JL, Gómez JM, Vargas P. Corolla morphology influences diversification rates in bifid toadflaxes (Linaria sect. Versicolores). ANNALS OF BOTANY 2013; 112:1705-22. [PMID: 24142920 PMCID: PMC3838546 DOI: 10.1093/aob/mct214] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS The role of flower specialization in plant speciation and evolution remains controversial. In this study the evolution of flower traits restricting access to pollinators was analysed in the bifid toadflaxes (Linaria sect. Versicolores), a monophyletic group of ~30 species and subspecies with highly specialized corollas. METHODS A time-calibrated phylogeny based on both nuclear and plastid DNA sequences was obtained using a coalescent-based method, and flower morphology was characterized by means of morphometric analyses. Directional trends in flower shape evolution and trait-dependent diversification rates were jointly analysed using recently developed methods, and morphological shifts were reconstructed along the phylogeny. Pollinator surveys were conducted for a representative sample of species. KEY RESULTS A restrictive character state (narrow corolla tube) was reconstructed in the most recent common ancestor of Linaria sect. Versicolores. After its early loss in the most species-rich clade, this character state has been convergently reacquired in multiple lineages of this clade in recent times, yet it seems to have exerted a negative influence on diversification rates. Comparative analyses and pollinator surveys suggest that the narrow- and broad-tubed flowers are evolutionary optima representing divergent strategies of pollen placement on nectar-feeding insects. CONCLUSIONS The results confirm that different forms of floral specialization can lead to dissimilar evolutionary success in terms of diversification. It is additionally suggested that opposing individual-level and species-level selection pressures may have driven the evolution of pollinator-restrictive traits in bifid toadflaxes.
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Affiliation(s)
- Mario Fernández-Mazuecos
- Departamento de Biodiversidad y Conservación, Real Jardín Botánico (RJB-CSIC), Plaza de Murillo 2, 28014 Madrid, Spain
- For correspondence. E-mail
| | - José Luis Blanco-Pastor
- Departamento de Biodiversidad y Conservación, Real Jardín Botánico (RJB-CSIC), Plaza de Murillo 2, 28014 Madrid, Spain
| | - José M. Gómez
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (EEZA-CSIC), Ctra. Sacramento s/n, La Cañada de San Urbano, 04120 Almería, Spain
- Departamento de Ecología, Universidad de Granada, Avenida de Fuente Nueva s/n, 18071 Granada, Spain
| | - Pablo Vargas
- Departamento de Biodiversidad y Conservación, Real Jardín Botánico (RJB-CSIC), Plaza de Murillo 2, 28014 Madrid, Spain
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Savriama Y, Gómez JM, Perfectti F, Klingenberg CP. Geometric morphometrics of corolla shape: dissecting components of symmetric and asymmetric variation in Erysimum mediohispanicum (Brassicaceae). THE NEW PHYTOLOGIST 2012; 196:945-954. [PMID: 22988918 DOI: 10.1111/j.1469-8137.2012.04312.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 08/06/2012] [Indexed: 05/14/2023]
Abstract
Symmetry is an important feature of floral structure, and floral symmetries are diverse and often complex. We use a new morphometric approach for analysing shapes with complex types of symmetry, which partitions shape variation into a component of symmetric variation and different components of asymmetry. This approach, based on the mathematical theory of symmetry groups, can be used for landmark configurations with any type of symmetry and is therefore promising as a general framework for morphometric analyses of floral symmetry and asymmetry. We demonstrate this approach by quantifying floral shape variation in a wild population of Erysimum mediohispanicum (Brassicaceae). Flowers of this species are disymmetric, so that the symmetry in the left-right and adaxial-abaxial directions can be considered separately and in combination. Both principal component analysis and Procrustes ANOVA indicate that symmetric variation accounts for most of the total variance and that adaxial-abaxial asymmetry is the dominant component of fluctuating asymmetry. Each component is associated with specific patterns of shape variation. These results illustrate the potential of the new method and suggest new areas for future research. The new morphometric approach is promising for further analyses of floral symmetry and asymmetry in evolutionary and developmental contexts.
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Affiliation(s)
- Yoland Savriama
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
- UMR 7205 CP 50 Entomologie/service Hyménoptères, Muséum National d'Histoire Naturelle, 45 rue Buffon, 75005, Paris, France
- Department of Biological Sciences St. Albert Hall, Rm 272 St. John's University, 8000 Utopia Parkway Queens, NY, 11439, USA
| | - José María Gómez
- Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, E-18071, Granada, Spain
| | - Francisco Perfectti
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, E-18071, Granada, Spain
| | - Christian Peter Klingenberg
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
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