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Escudero M, Arroyo JM, Sánchez-Ramírez S, Jordano P. Founder events and subsequent genetic bottlenecks underlie karyotype evolution in the Ibero-North African endemic Carex helodes. ANNALS OF BOTANY 2024; 133:871-882. [PMID: 37400416 PMCID: PMC11082475 DOI: 10.1093/aob/mcad087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 06/29/2023] [Indexed: 07/05/2023]
Abstract
BACKGROUND AND AIMS Despite chromosomal evolution being one of the major drivers of diversification in plants, we do not yet have a clear view of how new chromosome rearrangements become fixed within populations, which is a crucial step forward for understanding chromosomal speciation. METHODS In this study, we test the role of genetic drift in the establishment of new chromosomal variants in the context of hybrid dysfunction models of chromosomal speciation. We genotyped 178 individuals from seven populations (plus 25 seeds from one population) across the geographical range of Carex helodes (Cyperaceae). We also characterized karyotype geographical patterns of the species across its distribution range. For one of the populations, we performed a detailed study of the fine-scale, local spatial distribution of its individuals and their genotypes and karyotypes. KEY RESULTS Synergistically, phylogeographical and karyotypic evidence revealed two main genetic groups: southwestern Iberian Peninsula vs. northwestern African populations; and within Europe our results suggest a west-to-east expansion with signals of genetic bottlenecks. Additionally, we inferred a pattern of descending dysploidy, plausibly as a result of a west-to-east process of post-glacial colonization in Europe. CONCLUSIONS Our results give experimental support to the role of geographical isolation, drift and inbreeding in the establishment of new karyotypes, which is key in the speciation models of hybrid dysfunction.
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Affiliation(s)
- Marcial Escudero
- Department of Plant Biology and Ecology, University of Seville, 41012 Seville, Spain
- Department of Integrative Ecology, Doñana Biological Station, CSIC, 41092 Seville, Spain
| | - Juan Miguel Arroyo
- Department of Integrative Ecology, Doñana Biological Station, CSIC, 41092 Seville, Spain
| | - Santiago Sánchez-Ramírez
- Department of Ecology and Evolutionary Biology, University of Toronto, M5S 3B2 Toronto, Ontario, Canada
| | - Pedro Jordano
- Department of Plant Biology and Ecology, University of Seville, 41012 Seville, Spain
- Department of Integrative Ecology, Doñana Biological Station, CSIC, 41092 Seville, Spain
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2
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Augustijnen H, Bätscher L, Cesanek M, Chkhartishvili T, Dincă V, Iankoshvili G, Ogawa K, Vila R, Klopfstein S, de Vos JM, Lucek K. A macroevolutionary role for chromosomal fusion and fission in Erebia butterflies. SCIENCE ADVANCES 2024; 10:eadl0989. [PMID: 38630820 PMCID: PMC11023530 DOI: 10.1126/sciadv.adl0989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024]
Abstract
The impact of large-scale chromosomal rearrangements, such as fusions and fissions, on speciation is a long-standing conundrum. We assessed whether bursts of change in chromosome numbers resulting from chromosomal fusion or fission are related to increased speciation rates in Erebia, one of the most species-rich and karyotypically variable butterfly groups. We established a genome-based phylogeny and used state-dependent birth-death models to infer trajectories of karyotype evolution. We demonstrated that rates of anagenetic chromosomal changes (i.e., along phylogenetic branches) exceed cladogenetic changes (i.e., at speciation events), but, when cladogenetic changes occur, they are mostly associated with chromosomal fissions rather than fusions. We found that the relative importance of fusion and fission differs among Erebia clades of different ages and that especially in younger, more karyotypically diverse clades, speciation is more frequently associated with cladogenetic chromosomal changes. Overall, our results imply that chromosomal fusions and fissions have contrasting macroevolutionary roles and that large-scale chromosomal rearrangements are associated with bursts of species diversification.
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Affiliation(s)
- Hannah Augustijnen
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Livio Bätscher
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Martin Cesanek
- Slovak Entomological Society, Slovak Academy of Sciences, Bratislava 1, Slovakia
| | | | - Vlad Dincă
- Ecology and Genetics Research Unit, University of Oulu, 90570 Oulu, Finland
| | | | - Kota Ogawa
- Faculty of Social and Cultural Studies, Kyushu University, Fukuoka 819-0395, Japan
- Insect Sciences and Creative Entomology Center, Kyushu University, Fukuoka 819-0395, Japan
| | - Roger Vila
- Institut de Biologia Evolutiva (CSIC-Univ. Pompeu Fabra), 08003 Barcelona, Spain
| | - Seraina Klopfstein
- Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
- Life Sciences, Natural History Museum Basel, 4051 Basel, Switzerland
| | - Jurriaan M. de Vos
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
| | - Kay Lucek
- Department of Environmental Science, University of Basel, 4056 Basel, Switzerland
- Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
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3
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Márquez-Corro JI, Martín-Bravo S, Blanco-Pastor JL, Luceño M, Escudero M. The holocentric chromosome microevolution: From phylogeographic patterns to genomic associations with environmental gradients. Mol Ecol 2023. [PMID: 37795678 DOI: 10.1111/mec.17156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/19/2023] [Accepted: 09/22/2023] [Indexed: 10/06/2023]
Abstract
Geographic isolation and chromosome evolution are two of the major drivers of diversification in eukaryotes in general, and specifically, in plants. On one hand, range shifts induced by Pleistocene glacial oscillations deeply shaped the evolutionary trajectories of species in the Northern Hemisphere. On the other hand, karyotype variability within species or species complexes may have adaptive potential as different karyotypes may represent different recombination rates and linkage groups that may be associated with locally adapted genes or supergenes. Organisms with holocentric chromosomes are ideal to study the link between local adaptation and chromosome evolution, due to their high cytogenetic variability, especially when it seems to be related to environmental variation. Here, we integrate the study of the phylogeography, chromosomal evolution and ecological requirements of a plant species complex distributed in the Western Euro-Mediterranean region (Carex gr. laevigata, Cyperaceae). We aim to clarify the relative influence of these factors on population differentiation and ultimately on speciation. We obtained a well-resolved RADseq phylogeny that sheds light on the phylogeographic patterns of molecular and chromosome number variation, which are compatible with south-to-north postglacial migration. In addition, landscape genomics analyses identified candidate loci for local adaptation, and also strong significant associations between the karyotype and the environment. We conclude that karyotype distribution in C. gr. laevigata has been constrained by both range shift dynamics and local adaptation. Our study demonstrates that chromosome evolution may be responsible, at least partially, for microevolutionary patterns of population differentiation and adaptation in Carex.
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Affiliation(s)
- José Ignacio Márquez-Corro
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Seville, Spain
- Jodrell Laboratory, Department of Trait Diversity and Function, Royal Botanic Gardens, Kew, Richmond, UK
| | - Santiago Martín-Bravo
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Seville, Spain
| | - José Luis Blanco-Pastor
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Seville, Spain
- Departamento de Biología, IVAGRO, Universidad de Cádiz, Campus de Excelencia Internacional Agroalimentario (CeiA3), Cádiz, Spain
| | - Modesto Luceño
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Seville, Spain
| | - Marcial Escudero
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Seville, Spain
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4
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Escudero M, Marques A, Lucek K, Hipp AL. Genomic hotspots of chromosome rearrangements explain conserved synteny despite high rates of chromosome evolution in a holocentric lineage. Mol Ecol 2023. [PMID: 37486041 DOI: 10.1111/mec.17086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/26/2023] [Accepted: 07/11/2023] [Indexed: 07/25/2023]
Abstract
Holocentric organisms, unlike typical monocentric organisms, have kinetochore activity distributed along almost the whole length of the chromosome. Because of this, chromosome rearrangements through fission and fusion are more likely to become fixed in holocentric species, which may account for the extraordinary rates of chromosome evolution that many holocentric lineages exhibit. Long blocks of genome synteny have been reported in animals with holocentric chromosomes despite high rates of chromosome rearrangements. Nothing is known from plants, however, despite the fact that holocentricity appears to have played a key role in the diversification of one of the largest angiosperm genera, Carex (Cyperaceae). In the current study, we compared genomes of Carex species and a distantly related Cyperaceae species to characterize conserved and rearranged genome regions. Our analyses span divergence times ranging between 2 and 50 million years. We also compared a C. scoparia chromosome-level genome assembly with a linkage map of the same species to study rearrangements at a population level and suppression of recombination patterns. We found longer genome synteny blocks than expected under a null model of random rearrangement breakpoints, even between very distantly related species. We also found repetitive DNA to be non-randomly associated with holocentromeres and rearranged regions of the genome. The evidence of conserved synteny in sedges despite high rates of chromosome fission and fusion suggests that conserved genomic hotspots of chromosome evolution related to repetitive DNA shape the evolution of recombination, gene order and crossability in sedges. This finding may help explain why sedges are able to maintain species cohesion even in the face of high interspecific chromosome rearrangements.
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Affiliation(s)
- Marcial Escudero
- Department of Plant Biology and Ecology, University of Seville, Sevilla, Spain
| | - André Marques
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Kay Lucek
- Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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5
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Planta J, Liang YY, Xin H, Chansler MT, Prather LA, Jiang N, Jiang J, Childs KL. Chromosome-scale genome assemblies and annotations for Poales species Carex cristatella, Carex scoparia, Juncus effusus, and Juncus inflexus. G3 GENES|GENOMES|GENETICS 2022; 12:6670624. [PMID: 35976112 PMCID: PMC9526063 DOI: 10.1093/g3journal/jkac211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 07/18/2022] [Indexed: 12/03/2022]
Abstract
The majority of sequenced genomes in the monocots are from species belonging to Poaceae, which include many commercially important crops. Here, we expand the number of sequenced genomes from the monocots to include the genomes of 4 related cyperids: Carex cristatella and Carex scoparia from Cyperaceae and Juncus effusus and Juncus inflexus from Juncaceae. The high-quality, chromosome-scale genome sequences from these 4 cyperids were assembled by combining whole-genome shotgun sequencing of Nanopore long reads, Illumina short reads, and Hi-C sequencing data. Some members of the Cyperaceae and Juncaceae are known to possess holocentric chromosomes. We examined the repeat landscapes in our sequenced genomes to search for potential repeats associated with centromeres. Several large satellite repeat families, comprising 3.2–9.5% of our sequenced genomes, showed dispersed distribution of large satellite repeat clusters across all Carex chromosomes, with few instances of these repeats clustering in the same chromosomal regions. In contrast, most large Juncus satellite repeats were clustered in a single location on each chromosome, with sporadic instances of large satellite repeats throughout the Juncus genomes. Recognizable transposable elements account for about 20% of each of the 4 genome assemblies, with the Carex genomes containing more DNA transposons than retrotransposons while the converse is true for the Juncus genomes. These genome sequences and annotations will facilitate better comparative analysis within monocots.
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Affiliation(s)
- Jose Planta
- Department of Plant Biology, Michigan State University , East Lansing, MI 48824, USA
- National Institute of Molecular Biology and Biotechnology, University of the Philippines , Diliman, Quezon City 1101, Philippines
| | - Yu-Ya Liang
- Department of Plant Biology, Michigan State University , East Lansing, MI 48824, USA
| | - Haoyang Xin
- Department of Plant Biology, Michigan State University , East Lansing, MI 48824, USA
| | - Matthew T Chansler
- Department of Plant Biology, Michigan State University , East Lansing, MI 48824, USA
| | - L Alan Prather
- Department of Plant Biology, Michigan State University , East Lansing, MI 48824, USA
| | - Ning Jiang
- Department of Horticulture, MSU AgBioResearch, Michigan State University , East Lansing, MI 48824, USA
| | - Jiming Jiang
- Department of Plant Biology, Michigan State University , East Lansing, MI 48824, USA
- Department of Horticulture, MSU AgBioResearch, Michigan State University , East Lansing, MI 48824, USA
| | - Kevin L Childs
- Department of Plant Biology, Michigan State University , East Lansing, MI 48824, USA
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6
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Lucek K, Augustijnen H, Escudero M. A holocentric twist to chromosomal speciation? Trends Ecol Evol 2022; 37:655-662. [PMID: 35484024 DOI: 10.1016/j.tree.2022.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 10/18/2022]
Abstract
Chromosomal rearrangements trigger speciation by acting as barriers to gene flow. However, the underlying theory was developed with monocentric chromosomes in mind. Holocentric chromosomes, lacking a centromeric region, have repeatedly evolved and account for a significant fraction of extant biodiversity. Because chromosomal rearrangements may be more likely retained in holocentric species, holocentricity could provide a twist to chromosomal speciation. Here, we discuss how the abundance of chromosome-scale genomes, combined with novel analytical tools, offer the opportunity to assess the impacts of chromosomal rearrangements on rates of speciation by outlining a phylogenetic framework that aligns with the two major lines of chromosomal speciation theory. We further highlight how holocentric species could help to test for causal roles of chromosomal rearrangements in speciation.
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Affiliation(s)
- Kay Lucek
- Department of Environmental Sciences, University of Basel, Schönbeinstrasse 6, 4056 Basel, Switzerland.
| | - Hannah Augustijnen
- Department of Environmental Sciences, University of Basel, Schönbeinstrasse 6, 4056 Basel, Switzerland
| | - Marcial Escudero
- Department of Plant Biology and Ecology, University of Seville, Reina Mercedes, ES-41012 Seville, Spain
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7
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Kuznetsova VG, Gavrilov-Zimin IA, Grozeva SM, Golub NV. Comparative analysis of chromosome numbers and sex chromosome systems in Paraneoptera (Insecta). COMPARATIVE CYTOGENETICS 2021; 15:279-327. [PMID: 34616525 PMCID: PMC8490342 DOI: 10.3897/compcytogen.v15.i3.71866] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/06/2021] [Indexed: 05/28/2023]
Abstract
This article is part (the 4th article) of the themed issue (a monograph) "Aberrant cytogenetic and reproductive patterns in the evolution of Paraneoptera". The purpose of this article is to consider chromosome structure and evolution, chromosome numbers and sex chromosome systems, which all together constitute the chromosomal basis of reproduction and are essential for reproductive success. We are based on our own observations and literature data available for all major lineages of Paraneoptera including Zoraptera (angel insects), Copeognatha (=Psocoptera; bark lice), Parasita (=Phthiraptera s. str; true lice), Thysanoptera (thrips), Homoptera (scale insects, aphids, jumping plant-lice, whiteflies, and true hoppers), Heteroptera (true bugs), and Coleorrhyncha (moss bugs). Terminology, nomenclature, classification, and the study methods are given in the first paper of the issue (Gavrilov-Zimin et al. 2021).
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Affiliation(s)
- Valentina G. Kuznetsova
- Zoological Institute, Russian Academy of Sciences, Universitetskaya emb. 1, St. Petersburg, 199034, RussiaZoological Institute, Russian Academy of SciencesSt. PetersburgRussia
| | - Ilya A. Gavrilov-Zimin
- Zoological Institute, Russian Academy of Sciences, Universitetskaya emb. 1, St. Petersburg, 199034, RussiaZoological Institute, Russian Academy of SciencesSt. PetersburgRussia
| | - Snejana M. Grozeva
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Blvd Tsar Osvoboditel 1, Sofia 1000, BulgariaInstitute of Biodiversity and Ecosystem Research, Bulgarian Academy of SciencesSofiaBulgaria
| | - Natalia V. Golub
- Zoological Institute, Russian Academy of Sciences, Universitetskaya emb. 1, St. Petersburg, 199034, RussiaZoological Institute, Russian Academy of SciencesSt. PetersburgRussia
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8
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Abstract
Holocentric chromosomes possess multiple kinetochores along their length rather than the single centromere typical of other chromosomes [1]. They have been described for the first time in cytogenetic experiments dating from 1935 and, since this first observation, the term holocentric chromosome has referred to chromosomes that: i. lack the primary constriction corresponding to centromere observed in monocentric chromosomes [2]; ii. possess multiple kinetochores dispersed along the chromosomal axis so that microtubules bind to chromosomes along their entire length and move broadside to the pole from the metaphase plate [3]. These chromosomes are also termed holokinetic, because, during cell division, chromatids move apart in parallel and do not form the classical V-shaped figures typical of monocentric chromosomes [4–6]. Holocentric chromosomes evolved several times during both animal and plant evolution and are currently reported in about eight hundred diverse species, including plants, insects, arachnids and nematodes [7,8]. As a consequence of their diffuse kinetochores, holocentric chromosomes may stabilize chromosomal fragments favouring karyotype rearrangements [9,10]. However, holocentric chromosome may also present limitations to crossing over causing a restriction of the number of chiasma in bivalents [11] and may cause a restructuring of meiotic divisions resulting in an inverted meiosis [12].
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Affiliation(s)
- Mauro Mandrioli
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Modena, Italy
- * E-mail:
| | - Gian Carlo Manicardi
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Modena, Italy
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9
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Chung KS, Hoshino T, Masaki T, Im HT, Ji SJ. Chromosome Counts of Six Korean Carex Species (Cyperaceae). CYTOLOGIA 2018. [DOI: 10.1508/cytologia.83.229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Takuji Hoshino
- Department of Biosphere-Geosphere Science, Faculty of Biosphere-Geosphere Science, Okayama University of Science
| | - Tomomi Masaki
- Department of Biosphere-Geosphere Science, Faculty of Biosphere-Geosphere Science, Okayama University of Science
| | - Hyoung-Tak Im
- Department of Division of Biological Science, Chonnam National University
| | - Seong-Jin Ji
- Facility Management Division, National Science Museum
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10
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Escudero M, Hahn M, Hipp AL. RAD-seq linkage mapping and patterns of segregation distortion in sedges: meiosis as a driver of karyotypic evolution in organisms with holocentric chromosomes. J Evol Biol 2018; 31:833-843. [PMID: 29573004 DOI: 10.1111/jeb.13267] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/08/2018] [Accepted: 03/08/2018] [Indexed: 12/12/2022]
Abstract
Meiotic drive, the class of meiotic mechanisms that drive unequal segregation of alleles among gametes, may be an important force in karyotype evolution. Its role in holocentric organisms, whose chromosomes lack localized centromeres, is poorly understood. We crossed two individuals of Carex scoparia (Cyperaceae) with different chromosome numbers (2n = 33II = 66 × 2n = 32II = 64) to obtain F1 individuals, which we then self-pollinated to obtain second-generation (F2) crosses. RAD-seq was performed for 191 individuals (including the parents, five F1 individuals and 184 F2 individuals). Our F2 linkage map based on stringent editing of the RAD-seq data set yielded 32 linkage groups. In the final map, 865 loci were located on a linkage map of 3966.99 cM (linkage groups ranged from 24.39 to 193.31 cM in length and contained 5-51 loci each). Three linkage groups exhibit more loci under segregation distortion than expected by chance; within linkage groups, loci exhibiting segregation distortion are clustered. This finding implicates meiotic drive in the segregation of chromosome variants, suggesting that selection of chromosome variants in meiosis may contribute to the establishment and fixation of chromosome variants in Carex, which is renowned for high chromosomal and species diversity. This is an important finding as previous studies demonstrate that chromosome divergence may play a key role in differentiation and speciation in Carex.
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Affiliation(s)
- Marcial Escudero
- The Morton Arboretum, Lisle, IL, USA.,Botany Department, Field Museum of Natural History, Chicago, IL, USA.,Department of Plant Biology and Ecology, Universidad de Sevilla, Sevilla, Spain
| | | | - Andrew L Hipp
- The Morton Arboretum, Lisle, IL, USA.,Botany Department, Field Museum of Natural History, Chicago, IL, USA
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Schmidt L, Fischer M, Oja T. Two closely related species differ in their regional genetic differentiation despite admixing. AOB PLANTS 2018; 10:ply007. [PMID: 29479408 PMCID: PMC5817946 DOI: 10.1093/aobpla/ply007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/09/2018] [Indexed: 06/08/2023]
Abstract
Regional genetic differentiation within species is often addressed in evolutionary ecology and conservation biology. Here, we address regional differentiation in two closely related hybridizing taxa, the perennial sedges Carex flava and C. viridula and their hybrid C. × subviridula in 37 populations in the north and centre of their distribution range in Europe (Estonia, Lowland (<1000 m a.s.l.) and Highland Switzerland) using 10 putative microsatellite loci. We ask whether regional differentiation was larger in the less common taxon C. viridula or whether, possibly due to hybridization, it was similar between taxa. Our results showed similar, low to moderate genetic diversity for the three studied taxa. In total, we found 12 regional species-specific alleles. Analysis of molecular variance (AMOVA), STRUCTURE and multidimensional scaling analysis showed regional structure in genetic variation, where intraspecific differentiation between regions was lower for C. flava (AMOVA: 6.84 %) than for C. viridula (20.77 %) or C. × subviridula (18.27 %) populations. Hybrids differed from the parental taxa in the two regions where they occurred, i.e. in Estonia and Lowland Switzerland. We conclude that C. flava and C. viridula clearly differ from each other genetically, that there is pronounced regional differentiation and that, despite hybridization, this regional differentiation is more pronounced in the less common taxon, C. viridula. We encourage future studies on hybridizing taxa to work with plant populations from more than one region.
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Affiliation(s)
- Lisanna Schmidt
- Institute of Ecology and Earth Sciences, Department of Botany, University of Tartu, Tartu, Estonia
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Markus Fischer
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
- Botanical Garden, University of Bern, Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Tatjana Oja
- Institute of Ecology and Earth Sciences, Department of Botany, University of Tartu, Tartu, Estonia
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12
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Do holocentric chromosomes represent an evolutionary advantage? A study of paired analyses of diversification rates of lineages with holocentric chromosomes and their monocentric closest relatives. Chromosome Res 2017; 26:139-152. [PMID: 29043597 DOI: 10.1007/s10577-017-9566-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/05/2017] [Accepted: 10/06/2017] [Indexed: 10/18/2022]
Abstract
Despite most of the cytogenetic research is focused on monocentric chromosomes, chromosomes with kinetochoric activity localized in a single centromere, several studies have been centered on holocentric chromosomes which have diffuse kinetochoric activity along the chromosomes. The eukaryotic organisms that present this type of chromosomes have been relatively understudied despite they constitute rather diversified species lineages. On the one hand, holocentric chromosomes may present intrinsic benefits (chromosome mutations such as fissions and fusions are potentially neutral in holocentrics). On the other hand, they present restrictions to the spatial separation of the functions of recombination and segregation during meiotic divisions (functions that may interfere), separation that is found in monocentric chromosomes. In this study, we compare the diversification rates of all known holocentric lineages in animals and plants with their most related monocentric lineages in order to elucidate whether holocentric chromosomes constitute an evolutionary advantage in terms of diversification and species richness. The results showed that null hypothesis of equal mean diversification rates cannot be rejected, leading us to surmise that shifts in diversification rates between holocentric and monocentric lineages might be due to other factors, such as the idiosyncrasy of each lineage or the interplay of evolutionary selections with the benefits of having either monocentric or holocentric chromosomes.
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13
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Escudero M, Hahn M, Brown BH, Lueders K, Hipp AL. Chromosomal rearrangements in holocentric organisms lead to reproductive isolation by hybrid dysfunction: The correlation between karyotype rearrangements and germination rates in sedges. AMERICAN JOURNAL OF BOTANY 2016; 103:1529-36. [PMID: 27558707 DOI: 10.3732/ajb.1600051] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 06/14/2016] [Indexed: 05/13/2023]
Abstract
PREMISE OF THE STUDY Understanding the drivers of speciation is a central task of evolutionary biology. Chromosomal rearrangements are known to play an important role in species diversification, but the role of rearrangements of holocentric chromosomes-chromosomes without localized centromeres-is poorly understood. METHODS We made numerous artificial crosses between Carex scoparia individuals of different diploid chromosome numbers and, for comparison, between individuals of the same chromosome number. We studied chromosome pairing and chromosomal rearrangements in the F1 individuals using light microscopy. We then estimated germination rates as a function of geographic distance, genetic distance, chromosome number differences in parents, and pairing irregularities in F1 individuals, using generalized least squares to fit alternative regression models. KEY RESULTS The most informative predictors of germination rates in the F1 generation are chromosome number differences and minimum number of chromosome pairing irregularities in the F1 individuals. Genetic and geographic distances between parents are not significant predictors. CONCLUSIONS Holocentric chromosomal rearrangements play an important role in postzygotic reproductive isolation in Carex through F1 hybrid inviability and sterility. Hybrid dysfunction seems to be a suitable model for chromosomal speciation when there are several chromosomal rearrangements between parents. However, we have not tested the hypothesis that genome rearrangements may also play an important role in suppressing recombination between cytogenetically divergent populations.
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Affiliation(s)
- Marcial Escudero
- The Morton Arboretum, 4100 Illinois Route 53, Lisle, Illinois 60532 USA Department of Botany, The Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, Illinois 60605 USA Department of Plant Biology and Ecology, University of Seville, Reina Mercedes sn 41010 Seville, Spain.
| | - Marlene Hahn
- The Morton Arboretum, 4100 Illinois Route 53, Lisle, Illinois 60532 USA
| | - Bethany H Brown
- The Morton Arboretum, 4100 Illinois Route 53, Lisle, Illinois 60532 USA
| | - Kate Lueders
- The Morton Arboretum, 4100 Illinois Route 53, Lisle, Illinois 60532 USA
| | - Andrew L Hipp
- The Morton Arboretum, 4100 Illinois Route 53, Lisle, Illinois 60532 USA Department of Botany, The Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, Illinois 60605 USA
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Escudero M, Maguilla E, Loureiro J, Castro M, Castro S, Luceño M. Genome size stability despite high chromosome number variation in Carex gr. laevigata. AMERICAN JOURNAL OF BOTANY 2015; 102:233-8. [PMID: 25667076 DOI: 10.3732/ajb.1400433] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
PREMISE OF THE STUDY In organisms with holocentric chromosomes like Carex species, chromosome number evolution has been hypothesized to be a result of fission, fusion, and/or translocation events. Negative, positive, or the absence of correlations have been found between chromosome number and genome size in Carex. METHODS Using the inferred diploid chromosome number and 80 genome size measurements from 26 individuals and 20 populations of Carex gr. laevigata, we tested the null hypothesis of chromosome number evolution by duplication and deletion of whole chromosomes. KEY RESULTS Our results show a significant positive correlation between genome size and chromosome number, but the slope of such correlation supports the hypothesis of proliferation and removal of repetitive DNA fragments to explain genome size variation rather than duplication and deletion of whole chromosomes. CONCLUSIONS Our results refine the theory of the holokinetic drive: this mechanism is proposed to facilitate repetitive DNA removal (or any segmental deletion) when smaller homologous chromosomes are preferentially inherited, or repetitive DNA proliferation (or any segmental duplication) when larger homologs are preferred. This study sheds light on how karyotype evolution plays an important role in the diversification of the species of the genus Carex.
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Affiliation(s)
- Marcial Escudero
- Department of Integrative Ecology, Estación Biológica de Doñana (EBD-CSIC), Americo Vespucio sn 41092 Seville, Spain
| | - Enrique Maguilla
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Carretera de Utrera Km 1 sn 41013 Seville, Spain
| | - João Loureiro
- Centre for Functional Ecology, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Mariana Castro
- Centre for Functional Ecology, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Sílvia Castro
- Centre for Functional Ecology, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Modesto Luceño
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Carretera de Utrera Km 1 sn 41013 Seville, Spain
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Escudero M, Eaton DA, Hahn M, Hipp AL. Genotyping-by-sequencing as a tool to infer phylogeny and ancestral hybridization: A case study in Carex (Cyperaceae). Mol Phylogenet Evol 2014; 79:359-67. [DOI: 10.1016/j.ympev.2014.06.026] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/19/2014] [Accepted: 06/30/2014] [Indexed: 11/27/2022]
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