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He J, Lin S, Yu Z, Song A, Guan Z, Fang W, Chen S, Zhang F, Jiang J, Chen F, Wang H. Identification of 5S and 45S rDNA sites in Chrysanthemum species by using oligonucleotide fluorescence in situ hybridization (Oligo-FISH). Mol Biol Rep 2021; 48:21-31. [PMID: 33454907 DOI: 10.1007/s11033-020-06102-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/16/2020] [Indexed: 12/13/2022]
Abstract
Fluorescence in situ hybridization (FISH) is a conventional method used to visualize the distribution of DNA elements within a genome. To examine the relationships within the Chrysanthemum genus, ribosomal DNA (rDNA), a popular cytogenetic marker, was utilized as a probe for FISH within this genus. Based on the genome data of Chrysanthemum nankingense, C. seticuspe and its allied genera in the Compositae(Asteraceae), we explored rDNA sequences to design oligonucleotide probes and perform oligonucleotide fluorescence in situ hybridization (Oligo-FISH) in eight Chrysanthemum accessions. The results showed that the majority of 5S rDNA signals were located in subterminal chromosome regions and that the number of 5S rDNA sites might be tightly associated with ploidy. For 45S rDNA sites, the number and intensity of signals differed from those of previously investigated Chrysanthemum resources. These findings may provide an optimally reliable method of examining the chromosome composition and structural variation of Chrysanthemum and its related species and allow researchers to understand the evolutionary history and phylogenetic relationships of Chrysanthemum.
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Affiliation(s)
- Jun He
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Sisi Lin
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Zhongyu Yu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Aiping Song
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Zhiyong Guan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Weimin Fang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Sumei Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Fei Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Jiafu Jiang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Fadi Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Haibin Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing, China.
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Garcia S, Wendel JF, Borowska-Zuchowska N, Aïnouche M, Kuderova A, Kovarik A. The Utility of Graph Clustering of 5S Ribosomal DNA Homoeologs in Plant Allopolyploids, Homoploid Hybrids, and Cryptic Introgressants. FRONTIERS IN PLANT SCIENCE 2020; 11:41. [PMID: 32117380 PMCID: PMC7025596 DOI: 10.3389/fpls.2020.00041] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/13/2020] [Indexed: 05/18/2023]
Abstract
INTRODUCTION Ribosomal DNA (rDNA) loci have been widely used for identification of allopolyploids and hybrids, although few of these studies employed high-throughput sequencing data. Here we use graph clustering implemented in the RepeatExplorer (RE) pipeline to analyze homoeologous 5S rDNA arrays at the genomic level searching for hybridogenic origin of species. Data were obtained from more than 80 plant species, including several well-defined allopolyploids and homoploid hybrids of different evolutionary ages and from widely dispersed taxonomic groups. RESULTS (i) Diploids show simple circular-shaped graphs of their 5S rDNA clusters. In contrast, most allopolyploids and other interspecific hybrids exhibit more complex graphs composed of two or more interconnected loops representing intergenic spacers (IGS). (ii) There was a relationship between graph complexity and locus numbers. (iii) The sequences and lengths of the 5S rDNA units reconstituted in silico from k-mers were congruent with those experimentally determined. (iv) Three-genomic comparative cluster analysis of reads from allopolyploids and progenitor diploids allowed identification of homoeologous 5S rRNA gene families even in relatively ancient (c. 1 Myr) Gossypium and Brachypodium allopolyploids which already exhibit uniparental partial loss of rDNA repeats. (v) Finally, species harboring introgressed genomes exhibit exceptionally complex graph structures. CONCLUSION We found that the cluster graph shapes and graph parameters (k-mer coverage scores and connected component index) well-reflect the organization and intragenomic homogeneity of 5S rDNA repeats. We propose that the analysis of 5S rDNA cluster graphs computed by the RE pipeline together with the cytogenetic analysis might be a reliable approach for the determination of the hybrid or allopolyploid plant species parentage and may also be useful for detecting historical introgression events.
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Affiliation(s)
- Sònia Garcia
- Institut Botànic de Barcelona (IBB, CSIC - Ajuntament de Barcelona), Barcelona, Spain
- Department of Molecular Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
| | - Jonathan F. Wendel
- Department of Ecology, Evolution & Organismal Biology, Iowa State University, Ames, IA, United States
| | - Natalia Borowska-Zuchowska
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Malika Aïnouche
- UMR CNRS 6553 ECOBIO, Université de Rennes 1, Rennes, France
| | - Alena Kuderova
- Department of Molecular Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
| | - Ales Kovarik
- Department of Molecular Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czechia
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Paštová L, Belyayev A, Mahelka V. Molecular cytogenetic characterisation of Elytrigia ×mucronata, a natural hybrid of E. intermedia and E. repens (Triticeae, Poaceae). BMC PLANT BIOLOGY 2019; 19:230. [PMID: 31151385 PMCID: PMC6544950 DOI: 10.1186/s12870-019-1806-y] [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: 08/01/2018] [Accepted: 04/26/2019] [Indexed: 05/18/2023]
Abstract
BACKGROUND Interspecific hybridisation resulting in polyploidy is one of the major driving forces in plant evolution. Here, we present data from the molecular cytogenetic analysis of three cytotypes of Elytrigia ×mucronata using sequential fluorescence (5S rDNA, 18S rDNA and pSc119.2 probes) and genomic in situ hybridisation (four genomic probes of diploid taxa, i.e., Aegilops, Dasypyrum, Hordeum and Pseudoroegneria). RESULTS The concurrent presence of Hordeum (descended from E. repens) and Dasypyrum + Aegilops (descended from E. intermedia) chromosome sets in all cytotypes of E. ×mucronata confirmed the assumed hybrid origin of the analysed plants. The following different genomic constitutions were observed for E. ×mucronata. Hexaploid plants exhibited three chromosome sets from Pseudoroegneria and one chromosome set each from Aegilops, Hordeum and Dasypyrum. Heptaploid plants harboured the six chromosome sets of the hexaploid plants and an additional Pseudoroegneria chromosome set. Nonaploid cytotypes differed in their genomic constitutions, reflecting different origins through the fusion of reduced and unreduced gametes. The hybridisation patterns of repetitive sequences (5S rDNA, 18S rDNA, and pSc119.2) in E. ×mucronata varied between and within cytotypes. Chromosome alterations that were not identified in the parental species were found in both heptaploid and some nonaploid plants. CONCLUSIONS The results confirmed that both homoploid hybridisation and heteroploid hybridisation that lead to the coexistence of four different haplomes within single hybrid genomes occur in Elytrigia allopolyploids. The chromosomal alterations observed in both heptaploid and some nonaploid plants indicated that genome restructuring occurs during and/or after the hybrids arose. Moreover, a specific chromosomal translocation detected in one of the nonaploids indicated that it was not a primary hybrid. Therefore, at least some of the hybrids are fertile. Hybridisation in Triticeae allopolyploids clearly and significantly contributes to genomic diversity. Different combinations of parental haplomes coupled with chromosomal alterations may result in the establishment of unique lineages, thus providing raw material for selection.
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Affiliation(s)
- Ladislava Paštová
- Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
- Department of Botany, Charles University, Benátská 2, 128 01 Prague, Czech Republic
| | - Alexander Belyayev
- Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
| | - Václav Mahelka
- Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
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Ishchenko OO, Panchuk ІІ, Andreev ІO, Kunakh VA, Volkov RA. Molecular Organization of 5S Ribosomal DNА of Deschapmpsia antarctica. CYTOL GENET+ 2018. [DOI: 10.3103/s0095452718060105] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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5
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Sergeeva EM, Shcherban AB, Adonina IG, Nesterov MA, Beletsky AV, Rakitin AL, Mardanov AV, Ravin NV, Salina EA. Fine organization of genomic regions tagged to the 5S rDNA locus of the bread wheat 5B chromosome. BMC PLANT BIOLOGY 2017; 17:183. [PMID: 29143604 PMCID: PMC5688495 DOI: 10.1186/s12870-017-1120-5] [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] [Indexed: 05/17/2023]
Abstract
BACKGROUND The multigene family encoding the 5S rRNA, one of the most important structurally-functional part of the large ribosomal subunit, is an obligate component of all eukaryotic genomes. 5S rDNA has long been a favored target for cytological and phylogenetic studies due to the inherent peculiarities of its structural organization, such as the tandem arrays of repetitive units and their high interspecific divergence. The complex polyploid nature of the genome of bread wheat, Triticum aestivum, and the technically difficult task of sequencing clusters of tandem repeats mean that the detailed organization of extended genomic regions containing 5S rRNA genes remains unclear. This is despite the recent progress made in wheat genomic sequencing. Using pyrosequencing of BAC clones, in this work we studied the organization of two distinct 5S rDNA-tagged regions of the 5BS chromosome of bread wheat. RESULTS Three BAC-clones containing 5S rDNA were identified in the 5BS chromosome-specific BAC-library of Triticum aestivum. Using the results of pyrosequencing and assembling, we obtained six 5S rDNA- containing contigs with a total length of 140,417 bp, and two sets (pools) of individual 5S rDNA sequences belonging to separate, but closely located genomic regions on the 5BS chromosome. Both regions are characterized by the presence of approximately 70-80 copies of 5S rDNA, however, they are completely different in their structural organization. The first region contained highly diverged short-type 5S rDNA units that were disrupted by multiple insertions of transposable elements. The second region contained the more conserved long-type 5S rDNA, organized as a single tandem array. FISH using probes specific to both 5S rDNA unit types showed differences in the distribution and intensity of signals on the chromosomes of polyploid wheat species and their diploid progenitors. CONCLUSION A detailed structural organization of two closely located 5S rDNA-tagged genomic regions on the 5BS chromosome of bread wheat has been established. These two regions differ in the organization of both 5S rDNA and the neighboring sequences comprised of transposable elements, implying different modes of evolution for these regions.
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Affiliation(s)
- Ekaterina M Sergeeva
- The Federal Research Center "Institute of Cytology and Genetics SB RAS", Novosibirsk, Russia
| | - Andrey B Shcherban
- The Federal Research Center "Institute of Cytology and Genetics SB RAS", Novosibirsk, Russia.
| | - Irina G Adonina
- The Federal Research Center "Institute of Cytology and Genetics SB RAS", Novosibirsk, Russia
| | - Michail A Nesterov
- The Federal Research Center "Institute of Cytology and Genetics SB RAS", Novosibirsk, Russia
| | - Alexey V Beletsky
- The Federal Research Center "Fundamentals of Biotechnology RAS", Moscow, Russia
| | - Andrey L Rakitin
- The Federal Research Center "Fundamentals of Biotechnology RAS", Moscow, Russia
| | - Andrey V Mardanov
- The Federal Research Center "Fundamentals of Biotechnology RAS", Moscow, Russia
| | - Nikolai V Ravin
- The Federal Research Center "Fundamentals of Biotechnology RAS", Moscow, Russia
- Faculty of Biology, Moscow State University, Moscow, Russia
| | - Elena A Salina
- The Federal Research Center "Institute of Cytology and Genetics SB RAS", Novosibirsk, Russia
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Baum BR, Edwards T, Johnson DA. What does the 5S rRNA multigene family tell us about the origin of the annual Triticeae (Poaceae)? Genome 2013; 56:245-66. [PMID: 23789993 DOI: 10.1139/gen-2012-0195] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have investigated the complex relationships among the annual genera within the tribe Triticeae through phylogenetic analyses of the 5S rRNA multigene family. Cloned sequences were assigned to groups of orthologous sequences, called unit classes, that were subjected to several analyses including BLAST (Basic Local Alignment Search Tool) searches to assess possible ancestral relationships with perennial genera; phylogenetic analyses using parsimony (Pars), maximum likelihood (ML), and Bayesian methods; and minimum reticulation networks from the Pars, ML, and Bayesian trees. In this study, we included genera with both annual and perennial species, such as Dasypyrum, Hordeum, and Secale. BLAST pointed to Pseudoroegneria (carrier of the St genome) and possibly Thinopyrum (carrier of the J genome) as the potential next of kin. However, Thinopyrum and Pseudoroegneria have never fallen together on the individual trees with the former generally associated with Crithopsis, Aegilops, Triticum, and Dasypyrum, while the latter is usually associated with the rest of the genera within Triticeae. The "long" unit classes placed Dasypyrum breviaristatum together with Dasypyrum villosum, whereas the "short" unit classes put them far apart on the trees. None of the gene trees alone was able to summarize the complex relationships among the genera, in line with previous results in the Triticeae. However, the application of tools designed to display phylogenetic networks was able to depict the complex links among the genera based on the short and the long gene trees, including the close link between Thinopyrum and Pseudoroegneria suggested by the phylogenetic analyses. In addition, our analyses provide support for the hypothesis that at least some annual Triticeae taxa are derived from their perennial relatives.
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Affiliation(s)
- B R Baum
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre, Neatby Building, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada.
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Seo JH, Bae HG, Park DH, Kim BS, Lee JW, Lee JI, Kim DH, Lee SW, Seo BB. Sequence polymorphisms in ribosomal RNA genes and variations in chromosomal loci of Oenothera odorata and O. laciniata. Genes Genomics 2013. [DOI: 10.1007/s13258-013-0084-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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8
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Fernández-Tajes J, Méndez J. Two different size classes of 5S rDNA units coexisting in the same tandem array in the razor clam Ensis macha: is this region suitable for phylogeographic studies? Biochem Genet 2011; 47:775-88. [PMID: 19633947 DOI: 10.1007/s10528-009-9276-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 01/05/2009] [Indexed: 11/29/2022]
Abstract
For a study of 5S ribosomal genes (rDNA) in the razor clam Ensis macha, the 5S rDNA region was amplified and sequenced. Two variants, so-called type I or short repeat (approximately 430 bp) and type II or long repeat (approximately 735 bp), appeared to be the main components of the 5S rDNA of this species. Their spacers differed markedly, both in length and nucleotide composition. The organization of the two variants was investigated by amplifying the genomic DNA with primers based on the sequence of the type I and type II spacers. PCR amplification products with primers EMLbF and EMSbR showed that the long and short repeats are associated within the same tandem array, suggesting an intermixed arrangement of both spacers. Nevertheless, amplifications carried out with inverse primers EMSinvF/R and EMLinvF/R revealed that some short and long repeats are contiguous in the same tandem array. This is the first report of the coexistence of two variable spacers in the same tandem array in bivalve mollusks.
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Affiliation(s)
- Juan Fernández-Tajes
- Department of Cell and Molecular Biology, Faculty of Sciences, University of A Coruña, Spain.
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9
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Sultana S, Bang JW, Choi HW. Organization of the 5S rRNA gene units in Korean Lilium species. Genes Genomics 2011. [DOI: 10.1007/s13258-010-0131-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Baum BR, Edwards T, Johnson DA. Codependence of repetitive sequence classes in genomes: phylogenetic analysis of 5S rDNA families in Hordeum (Triticeae: Poaceae). Genome 2010; 53:180-202. [PMID: 20237596 DOI: 10.1139/g09-096] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To complete our study of the genus Hordeum and to elaborate a phylogeny of species based upon 5S rDNA sequences, we have cloned and sequenced PCR amplicons from seven American polyploid species to generate 164 new 5S rRNA gene sequences. These sequences were analysed along with the more than 2000 5S rDNA sequences previously generated from the majority of species in Hordeum to provide a comprehensive picture of the distribution (presence or absence) of 5S rDNA unit classes (orthologous groups) in this genus as well as insights into the phylogeny of Hordeum. Testing of substitution models for each unit class based upon the consensus sequences of all the taxa as well as for each unit class within the genus found that the general best fit was TPM3uf+G, from which a maximum-likelihood tree was calculated. A novel application of cophylogenetic analysis, where relationships among unit classes were treated as host-parasite interactions, depicted some significant pair links under tests of randomness indicative of nonrandom codivergence among several unit classes within the same taxon. The previous classification of four genomic groups is reflected in combinations of unit classes, and it is proposed that current taxa developed from ancient diploidized paleopolyploids and that some were subjected to gene loss, i.e., unit class loss. Finally, separate phylogenetic analyses performed for the tetraploid and hexaploid species were used to derive a working model describing the phylogeny of the polyploid taxa from their putative diploid ancestry.
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Affiliation(s)
- Bernard R Baum
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre, Neatby Building, Ottawa, ON, Canada.
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11
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Seo JH, Seo BB. Independent chromosomal localization of two different size 5S rDNA of Allium victorialis var. platyphyllum by sequential fluorescence in situ hybridization in accordance with sequence polymorphism. Genes Genomics 2010. [DOI: 10.1007/s13258-009-0804-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Shcherban AB, Sergeeva EM, Badaeva ED, Salina EA. Analysis of 5S rDNA changes in synthetic allopolyploids Triticum × Aegilops. Mol Biol 2008. [DOI: 10.1134/s0026893308040080] [Citation(s) in RCA: 7] [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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13
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Raskina O, Barber JC, Nevo E, Belyayev A. Repetitive DNA and chromosomal rearrangements: speciation-related events in plant genomes. Cytogenet Genome Res 2008; 120:351-7. [PMID: 18504364 DOI: 10.1159/000121084] [Citation(s) in RCA: 219] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2007] [Indexed: 11/19/2022] Open
Abstract
Chromosomal change is one of the more hotly debated potential mechanisms of speciation. It has long been argued over whether--and to what degree--changes in chromosome structure contribute to reproductive isolation and, ultimately, speciation. In this review we do not aim to completely analyze accumulated data about chromosomal speciation but wish to draw attention to several critical points of speciation-related chromosomal change, namely: (a) interrelations between chromosomal rearrangements and repetitive DNA fraction; (b) mobility of ribosomal DNA clusters; and (c) rDNA and transposable elements as perpetual generators of genome instability.
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Affiliation(s)
- O Raskina
- Institute of Evolution, University of Haifa, Israel
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14
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Peng YY, Wei YM, Baum BR, Zheng YL. Molecular diversity of the 5S rRNA gene and genomic relationships in the genus Avena (Poaceae: Aveneae). Genome 2008; 51:137-54. [PMID: 18356948 DOI: 10.1139/g07-111] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The molecular diversity of the rDNA sequences (5S rDNA units) in 71 accessions from 26 taxa of Avena was evaluated. The analyses, based on 553 sequenced clones, indicated that there were 6 unit classes, named according to the haplomes (genomes) they putatively represent, namely the long A1, long B1, long M1, short C1, short D1, and short M1 unit classes. The long and short M1 unit classes were found in the tetraploid A. macrostachya, the only perennial species. The long M1 unit class was closely related to the short C1 unit class, while the short M1 unit class was closely related to the long A1 and long B1 unit classes. However, the short D1 unit class was more divergent from the other unit classes. There was only one unit class per haplome in Avena, whereas haplomes in the Triticeae often have two. Most of the sequences captured belonged to the long A1 unit class. Sequences identified as the long B1 unit class were found in the tetraploids A. abyssinica and A. vaviloviana and the diploids A. atlantica and A. longiglumis. The short C1 unit class was found in the diploid species carrying the C genome, i.e., A. clauda, A. eriantha, and A. ventricosa, and also in the diploid A. longiglumis, the tetraploids A. insularis and A. maroccana, and all the hexaploid species. The short D1 unit class was found in all the hexaploid species and two clones of A. clauda. It is noteworthy that in previous studies the B genome was found only in tetraploid species and the D genome only in hexaploid species. Unexpectedly, we found that various diploid Avena species contained the B1 and D1 units. The long B1 unit class was found in 3 accessions of the diploid A. atlantica (CN25849, CN25864, and CN25887) collected in Morocco and in 2 accessions of A. longiglumis (CIav9087 and CIav9089) collected in Algeria and Libya, respectively, whereas only 1 clone of A. clauda (CN21378) had the short D1 unit. Thus there might be a clue as to where to search for diploids carrying the B and D genomes. Avena longiglumis was found to be the most diverse species, possibly harboring the A, B, and C haplomes. The long M1 and short M1 are the unit classes typical of A. macrostachya. These results could explain the roles of A. clauda, A. longiglumis, and A. atlantica in the evolution of the genus Avena. Furthermore, one clone of the tetraploid A. murphyi was found to have sequences belonging to the short D1 unit class, which could indicate that A. murphyi might have been the progenitor of hexaploid oats and not, as postulated earlier, A. insularis. The evolution of Avena did not follow the molecular clock. The path inferred is that the C genome is more ancient than the A and B genomes and closer to the genome of A. macrostachya, the only existing perennial, which is presumed to be the most ancestral species in the genus.
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Affiliation(s)
- Yuan-Ying Peng
- Triticeae Research Institute, Sichuan Agricultural University, Yaan 625014, Sichuan, People's Republic of China
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15
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Zhu XY, Cai DT, Ding Y. Molecular and cytological characterization of 5S rDNA inOryzaspecies: genomic organization and phylogenetic implications. Genome 2008; 51:332-40. [DOI: 10.1139/g08-016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the molecular characteristics and chromosomal organization of 5S rDNA in the genus Oryza , including diploid and tetraploid species. A phylogenetic tree of Oryza species was constructed based on the non-transcribed spacer sequences of 5S rDNA, and some novel relationships were discovered. Specifically, comparative sequence analysis of 5S rDNA in several wild rice species showed unique characteristics inconsistent with the model of concerted evolution: (1) multiple distinct 5S rDNA types were detected within a species, leading to intraspecific divergence of 5S rDNA; (2) multiple identical 5S rDNA types were shared among species, resulting in interspecies clustering of 5S rDNA types; and (3) intraspecific nucleotide diversity was detected within a 5S rDNA class. Our results obtained by fluorescence in situ hybridization revealed that each rice species studied contained only one 5S rDNA locus with two hybridization sites, which were located on either chromosome 7 or chromosome 11. These results suggest that different 5S rDNA classes within the rice genome were arranged together and that one pair of 5S rDNA loci from a diploid progenitor of the tetraploid species might have been lost during evolution. Taken together, our data show that 5S rDNA in rice species is more informative at the gene level than at the chromosome level.
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Affiliation(s)
- Xiao-Yan Zhu
- Key Laboratory of the Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P.R. China
- College of Life Sciences, Hubei University, Wuhan 430072, P.R. China
| | - De-Tian Cai
- Key Laboratory of the Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P.R. China
- College of Life Sciences, Hubei University, Wuhan 430072, P.R. China
| | - Yi Ding
- Key Laboratory of the Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P.R. China
- College of Life Sciences, Hubei University, Wuhan 430072, P.R. China
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16
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Falistocco E, Passeri V, Marconi G. Investigations of 5S rDNA of Vitis vinifera L.: sequence analysis and physical mapping. Genome 2007; 50:927-38. [DOI: 10.1139/g07-070] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Here we report the first results of a study of 5S rDNA of Vitis vinifera . 5S rDNA sequences from seven genotypes were amplified by PCR, cloned, and sequenced. Three types of repeats were found. Two variants, denominated long repeat and short repeat, appeared to be the main components of the 5S rDNA of this species, since they were found in all genotypes analyzed. They differed markedly from each other in both the length and the nucleotide composition of the spacers. The third variant, classified as DEL short repeat, differs from the short repeat owing to a large deletion in the spacer region. It appears to be the most recent repeat type, since it was identified in only one genotype. The organization of the 5S rDNA repeat unit variants was investigated by amplifying the genomic DNA with primers designed on the sequence of the long and short spacers. The PCR-amplified fragments showed that the long repeat is associated with the other two repeats, indicating that in V. vinifera different repeat units coexist within the same tandem array. FISH analysis demonstrated that 5S rRNA genes are localized at a single locus. The variability of 5S rDNA repeats is discussed in relation to the putative allopolyploid origin of V. vinifera.
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Affiliation(s)
- E. Falistocco
- Dipartimento di Biologia Vegetale e Biotecnologie Agroambientali e Zootecniche, Università degli Studi di Perugia, Borgo XX Giugno, 06121 Perugia, Italy
| | - V. Passeri
- Dipartimento di Biologia Vegetale e Biotecnologie Agroambientali e Zootecniche, Università degli Studi di Perugia, Borgo XX Giugno, 06121 Perugia, Italy
| | - G. Marconi
- Dipartimento di Biologia Vegetale e Biotecnologie Agroambientali e Zootecniche, Università degli Studi di Perugia, Borgo XX Giugno, 06121 Perugia, Italy
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17
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Maughan PJ, Kolano BA, Maluszynska J, Coles ND, Bonifacio A, Rojas J, Coleman CE, Stevens MR, Fairbanks DJ, Parkinson SE, Jellen EN. Molecular and cytological characterization of ribosomal RNA genes in Chenopodium quinoa and Chenopodium berlandieri. Genome 2007; 49:825-39. [PMID: 16936791 DOI: 10.1139/g06-033] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nucleolus organizer region (NOR) and 5S ribosomal RNA (rRNA) genes are valuable as chromosome landmarks and in evolutionary studies. The NOR intergenic spacers (IGS) and 5S rRNA nontranscribed spacers (NTS) were PCR-amplified and sequenced from 5 cultivars of the Andean grain crop quinoa (Chenopodium quinoa Willd., 2n = 4x = 36) and a related wild ancestor (C. berlandieri Moq. subsp. zschackei (Murr) A. Zobel, 2n = 4x = 36). Length heterogeneity observed in the IGS resulted from copy number difference in subrepeat elements, small re arrangements, and species-specific indels, though the general sequence composition of the 2 species was highly similar. Fifteen of the 41 sequence polymorphisms identified among the C. quinoa lines were synapomorphic and clearly differentiated the highland and lowland ecotypes. Analysis of the NTS sequences revealed 2 basic NTS sequence classes that likely originated from the 2 allopolyploid subgenomes of C. quinoa. Fluorescence in situ hybridization (FISH) analysis showed that C. quinoa possesses an interstitial and a terminal pair of 5S rRNA loci and only 1 pair of NOR, suggesting a reduction in the number of rRNA loci during the evolution of this species. C. berlandieri exhibited variation in both NOR and 5S rRNA loci without changes in ploidy.
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Affiliation(s)
- P J Maughan
- Brigham Young University, Department of Plant & Animal Sciences, Provo, UT 84602, USA.
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18
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Singh D, Ahuja PS. 5S rDNA gene diversity in tea (Camellia sinensis (L.) O. Kuntze) and its use for variety identification. Genome 2006; 49:91-6. [PMID: 16462906 DOI: 10.1139/g05-065] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Variability in the organization of repeats of 5S rDNA is useful for phylogenetic studies in various crops. We found variable repeats of 5S rDNA gene in the genome of tea (Camellia sinensis (L.) O. Kuntze) during Southern hybridization. Variability in the repeats of 5S rDNA with specific restriction endonuleases (Sau3AI, BamHI, and ApoI) was analyzed in 28 different tea clones representing 3 types of tea. Our results clearly show that the 5S rDNA gene in tea could be used as a molecular marker to distinguish C. sinensis Chinary tea from the other important types of tea, namely Assamica and Cambod. Upon analysis with restriction endonucleases, the 5S rDNA gene in the tea genome was found to be heavily methylated.Key words: Camellia sinensis, 5S rDNA, DNA methylation, restriction endonucleases, molecular marker.
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Affiliation(s)
- Dharam Singh
- Institute of Himalayan Bioresource Technology, Palampur, India
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