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Zhang X, Ferree PM. PSRs: Selfish chromosomes that manipulate reproductive development. Semin Cell Dev Biol 2024; 159-160:66-73. [PMID: 38394822 DOI: 10.1016/j.semcdb.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 01/17/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024]
Abstract
B chromosomes are intriguing "selfish" genetic elements, many of which exhibit higher-than-Mendelian transmission. This perspective highlights a group of B chromosomes known as Paternal Sex Ratio chromosomes (PSRs), which are found in several insects with haplo-diploid reproduction. PSRs harshly alter the organism's reproduction to facilitate their own inheritance. A manifestation of this effect is the conversion of female destined individuals into males. Key to this conversion is the mysterious ability of PSRs to cause elimination of the sperm-inherited half of the genome during zygote formation. Here we discuss how PSRs were discovered, what is known about how they alter paternal chromatin dynamics to cause sex conversion, and how PSR-induced genome elimination is different from other forms of programmed genome elimination in different insects. PSRs also stand out because their DNA sequence compositions differ in remarkable ways from their insect's essential chromosomes, a characteristic suggestive of interspecies origins. Broadly, we also highlight poorly understood aspects of PSR dynamics that need to be investigated.
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Affiliation(s)
- Xinmi Zhang
- W. M. Keck Science Department, Pitzer and Scripps Colleges, Claremont, CA 91711, USA
| | - Patrick M Ferree
- W. M. Keck Science Department, Pitzer and Scripps Colleges, Claremont, CA 91711, USA.
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2
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Miura O, Toyoda A, Sakurai T. Chromosome-Scale Genome Assembly of the Freshwater Snail Semisulcospira habei from the Lake Biwa Drainage System. Genome Biol Evol 2023; 15:evad208. [PMID: 38014863 PMCID: PMC10683039 DOI: 10.1093/gbe/evad208] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2023] [Indexed: 11/29/2023] Open
Abstract
Semisulcospira habei is a freshwater snail species endemic to the Lake Biwa drainage and belongs to a species group radiated within the lake system. We report the chromosome-scale genome assembly of S. habei, including eight megascaffolds larger than 150 Mb. The genome assembly size is about 2.0 Gb with an N50 of 237 Mb. There are 41,547 protein-coding genes modeled by ab initio gene prediction based on the transcriptome data set, and the BUSCO completeness of the annotated genes was 92.2%. The repeat elements comprise approximately 76% of the genome assembly. The Hi-C contact map showed seven well-resolved scaffolds that correspond to the basic haploid chromosome number of S. habei inferred from the preceding karyotypic study, while it also exhibited one scaffold with a complicated mosaic pattern that is likely to represent the complex of multiple supernumerary chromosomes. The genome assembly reported here represents a high-quality genome resource in disentangling the genomic background of the adaptive radiation of Semisulcospira and also facilitates evolutionary studies in the superfamily Cerithioidea.
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Affiliation(s)
- Osamu Miura
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, Japan
| | - Atsushi Toyoda
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Tetsuya Sakurai
- Faculty of Agriculture and Marine Science, Kochi University, Nankoku, Kochi, Japan
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3
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Ebrahimzadegan R, Fuchs J, Chen J, Schubert V, Meister A, Houben A, Mirzaghaderi G. Meiotic segregation and post-meiotic drive of the Festuca pratensis B chromosome. Chromosome Res 2023; 31:26. [PMID: 37658970 PMCID: PMC10474989 DOI: 10.1007/s10577-023-09728-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/13/2023] [Accepted: 07/19/2023] [Indexed: 09/05/2023]
Abstract
In many species, the transmission of B chromosomes (Bs) does not follow the Mendelian laws of equal segregation and independent assortment. This deviation results in transmission rates of Bs higher than 0.5, a process known as "chromosome drive". Here, we studied the behavior of the 103 Mbp-large B chromosome of Festuca pratensis during all meiotic and mitotic stages of microsporogenesis. Mostly, the B chromosome of F. pratensis segregates during meiosis like standard A chromosomes (As). In some cases, the B passes through meiosis in a non-Mendelian segregation leading to their accumulation already in meiosis. However, a true drive of the B happens during the first pollen mitosis, by which the B preferentially migrates to the generative nucleus. During second pollen mitosis, B divides equally between the two sperms. Despite some differences in the frequency of drive between individuals with different numbers of Bs, at least 82% of drive was observed. Flow cytometry-based quantification of B-containing sperm nuclei agrees with the FISH data.
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Affiliation(s)
- Rahman Ebrahimzadegan
- Department of Plant Production and Genetics, Faculty of Agriculture, University of Kurdistan, Sanandaj, 66177-15175, Iran
| | - Jörg Fuchs
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
| | - Jianyong Chen
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
| | - Armin Meister
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany.
| | - Ghader Mirzaghaderi
- Department of Plant Production and Genetics, Faculty of Agriculture, University of Kurdistan, Sanandaj, 66177-15175, Iran.
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4
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Svačina R, Hloušková L, Karafiátová M, Bartoš J. Scoring the number of B chromosomes in Zea mays L. using droplet digital PCR assay. Plant Methods 2023; 19:43. [PMID: 37131220 PMCID: PMC10155399 DOI: 10.1186/s13007-023-01019-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/21/2023] [Indexed: 05/04/2023]
Abstract
BACKGROUND B chromosomes are classified as dispensable genomic components tolerated by cells, which are transmitted to progeny despite providing no benefit in most cases. They have been observed in over 2800 species of plants, animals and fungi, including numerous maize accessions. As maize is one of the most important crops worldwide, research on the maize B chromosome has been pioneering in the field. The characteristic of the B chromosome is its irregular inheritance. This results in offspring with a different number of B chromosomes compared to the parents. However, the exact number of B chromosomes in the studied plants is a crucial piece of information. Currently, assessing the number of B chromosomes in maize largely depends on cytogenetic analyses, which are laborious and time-consuming. We present an alternative approach based on the droplet digital PCR technique (ddPCR), which is faster, more efficient and provides the results within one day with the same level of accuracy. RESULTS In this study, we report a rapid and straightforward protocol for determining the number of B chromosomes in maize plants. We developed a droplet digital PCR assay using specific primers and a TaqMan probe for the B-chromosome-linked gene and a single-copy reference gene on maize chromosome 1. The performance of the assay was successfully verified by comparison with the results of cytogenetic analyses performed in parallel. CONCLUSIONS The protocol significantly improves the efficiency of B chromosome number assessment in maize compared to cytogenetic approaches. The assay has been developed to target conserved genomic regions and can therefore be applied to a wide range of diverged maize accessions. This universal approach can be modified for chromosome number detection in other species, not only for the B chromosome but also for any other chromosome in aneuploid constitution.
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Affiliation(s)
- Radim Svačina
- Institute of Experimental Botany of the Czech Academy of Sciences, Centre of Plant Structural and Functional Genomics, Šlechtitelů 31, 779 00, Olomouc, Czech Republic
- Plant Science Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
- KAUST Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Lucie Hloušková
- Institute of Experimental Botany of the Czech Academy of Sciences, Centre of Plant Structural and Functional Genomics, Šlechtitelů 31, 779 00, Olomouc, Czech Republic
- Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, 779 00, Olomouc, Czech Republic
| | - Miroslava Karafiátová
- Institute of Experimental Botany of the Czech Academy of Sciences, Centre of Plant Structural and Functional Genomics, Šlechtitelů 31, 779 00, Olomouc, Czech Republic
| | - Jan Bartoš
- Institute of Experimental Botany of the Czech Academy of Sciences, Centre of Plant Structural and Functional Genomics, Šlechtitelů 31, 779 00, Olomouc, Czech Republic.
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5
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Borodin P, Chen A, Forstmeier W, Fouché S, Malinovskaya L, Pei Y, Reifová R, Ruiz-Ruano FJ, Schlebusch SA, Sotelo-Muñoz M, Torgasheva A, Vontzou N, Suh A. Mendelian nightmares: the germline-restricted chromosome of songbirds. Chromosome Res 2022; 30:255-272. [PMID: 35416568 PMCID: PMC9508068 DOI: 10.1007/s10577-022-09688-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/07/2022] [Accepted: 03/16/2022] [Indexed: 11/03/2022]
Abstract
Germline-restricted chromosomes (GRCs) are accessory chromosomes that occur only in germ cells. They are eliminated from somatic cells through programmed DNA elimination during embryo development. GRCs have been observed in several unrelated animal taxa and show peculiar modes of non-Mendelian inheritance and within-individual elimination. Recent cytogenetic and phylogenomic evidence suggests that a GRC is present across the species-rich songbirds, but absent in non-passerine birds, implying that over half of all 10,500 bird species have extensive germline/soma genome differences. Here, we review recent insights gained from genomic, transcriptomic, and cytogenetic approaches with regard to the genetic content, phylogenetic distribution, and inheritance of the songbird GRC. While many questions remain unsolved in terms of GRC inheritance, elimination, and function, we discuss plausible scenarios and future directions for understanding this widespread form of programmed DNA elimination.
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Affiliation(s)
- Pavel Borodin
- Siberian Department, Russian Academy of Sciences, Institute of Cytology and Genetics, Prospekt Akademika Lavrent'yeva 10, 630090, Novosibirsk, Russia
| | - Augustin Chen
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, Science for Life Laboratory, 752 36, Uppsala, Sweden
| | - Wolfgang Forstmeier
- Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319, Seewiesen, Germany.
| | - Simone Fouché
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, Science for Life Laboratory, 752 36, Uppsala, Sweden.,School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TU, UK
| | - Lyubov Malinovskaya
- Siberian Department, Russian Academy of Sciences, Institute of Cytology and Genetics, Prospekt Akademika Lavrent'yeva 10, 630090, Novosibirsk, Russia
| | - Yifan Pei
- Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319, Seewiesen, Germany
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague, Czech Republic.
| | - Francisco J Ruiz-Ruano
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, Science for Life Laboratory, 752 36, Uppsala, Sweden.,School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TU, UK
| | - Stephen A Schlebusch
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague, Czech Republic
| | - Manuelita Sotelo-Muñoz
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague, Czech Republic
| | - Anna Torgasheva
- Siberian Department, Russian Academy of Sciences, Institute of Cytology and Genetics, Prospekt Akademika Lavrent'yeva 10, 630090, Novosibirsk, Russia.
| | - Niki Vontzou
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TU, UK
| | - Alexander Suh
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, Science for Life Laboratory, 752 36, Uppsala, Sweden. .,School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TU, UK.
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6
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Shi X, Yang H, Chen C, Hou J, Ji T, Cheng J, Birchler JA. Effect of aneuploidy of a non-essential chromosome on gene expression in maize. Plant J 2022; 110:193-211. [PMID: 34997647 PMCID: PMC9310612 DOI: 10.1111/tpj.15665] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 05/20/2023]
Abstract
The non-essential supernumerary maize (Zea mays) B chromosome (B) has recently been shown to contain active genes and to be capable of impacting gene expression of the A chromosomes. However, the effect of the B chromosome on gene expression is still unclear. In addition, it is unknown whether the accumulation of the B chromosome has a cumulative effect on gene expression. To examine these questions, the global expression of genes, microRNAs (miRNAs), and transposable elements (TEs) of leaf tissue of maize W22 plants with 0-7 copies of the B chromosome was studied. All experimental genotypes with B chromosomes displayed a trend of upregulated gene expression for a subset of A-located genes compared to the control. Over 3000 A-located genes are significantly differentially expressed in all experimental genotypes with the B chromosome relative to the control. Modulations of these genes are largely determined by the presence rather than the copy number of the B chromosome. By contrast, the expression of most B-located genes is positively correlated with B copy number, showing a proportional gene dosage effect. The B chromosome also causes increased expression of A-located miRNAs. Differentially expressed miRNAs potentially regulate their targets in a cascade of effects. Furthermore, the varied copy number of the B chromosome leads to the differential expression of A-located and B-located TEs. The findings provide novel insights into the function and properties of the B chromosome.
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Affiliation(s)
- Xiaowen Shi
- Division of Biological SciencesUniversity of MissouriColumbiaMissouri65211USA
- Present address:
College of Agriculture and BiotechnologyZhejiang UniversityHangzhou310058China
| | - Hua Yang
- Division of Biological SciencesUniversity of MissouriColumbiaMissouri65211USA
| | - Chen Chen
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriColumbiaMissouri65211USA
| | - Jie Hou
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriColumbiaMissouri65211USA
| | - Tieming Ji
- Department of StatisticsUniversity of MissouriColumbiaMissouri65211USA
| | - Jianlin Cheng
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriColumbiaMissouri65211USA
| | - James A. Birchler
- Division of Biological SciencesUniversity of MissouriColumbiaMissouri65211USA
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7
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Zadesenets KS, Rubtsov NB. B Chromosomes in Free-Living Flatworms of the Genus Macrostomum (Platyhelminthes, Macrostomorpha). Int J Mol Sci 2021; 22:13617. [PMID: 34948412 PMCID: PMC8708343 DOI: 10.3390/ijms222413617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/14/2021] [Accepted: 12/17/2021] [Indexed: 11/17/2022] Open
Abstract
B chromosomes (Bs) or supernumerary chromosomes are extra chromosomes in the species karyotype that can vary in its copy number. Bs are widespread in eukaryotes. Usually, the Bs of specimens collected from natural populations are the object of the B chromosome studies. We applied another approach analyzing the Bs in animals maintained under the laboratory conditions as lines and cultures. In this study, three species of the Macrostomum genus that underwent a recent whole-genome duplication (WGD) were involved. In laboratory lines of M. lignano and M. janickei, the frequency of Bs was less than 1%, while in the laboratory culture of M. mirumnovem, it was nearer 30%. Their number in specimens of the culture varied from 1 to 14. Mosaicism on Bs was discovered in parts of these animals. We analyzed the distribution of Bs among the worms of the laboratory cultures during long-term cultivation, the transmission rates of Bs in the progeny obtained from crosses of worms with different numbers of Bs, and from self-fertilized isolated worms. The DNA content of the Bs in M. mirumnovem was analyzed with the chromosomal in situ suppression (CISS) hybridization of microdissected DNA probes derived from A chromosomes (As). Bs mainly consisted of repetitive DNA. The cytogenetic analysis also revealed the divergence and high variation in large metacentric chromosomes (LMs) containing numerous regions enriched for repeats. The possible mechanisms of the appearance and evolution of Bs and LMs in species of the Macrostomum genus were also discussed.
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Affiliation(s)
- Kira S. Zadesenets
- The Federal Research Center Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia;
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8
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Imarazene B, Du K, Beille S, Jouanno E, Feron R, Pan Q, Torres-Paz J, Lopez-Roques C, Castinel A, Gil L, Kuchly C, Donnadieu C, Parrinello H, Journot L, Cabau C, Zahm M, Klopp C, Pavlica T, Al-Rikabi A, Liehr T, Simanovsky SA, Bohlen J, Sember A, Perez J, Veyrunes F, Mueller TD, Postlethwait JH, Schartl M, Herpin A, Rétaux S, Guiguen Y. A supernumerary "B-sex" chromosome drives male sex determination in the Pachón cavefish, Astyanax mexicanus. Curr Biol 2021; 31:4800-4809.e9. [PMID: 34496222 DOI: 10.1016/j.cub.2021.08.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/30/2021] [Accepted: 08/09/2021] [Indexed: 01/30/2023]
Abstract
Sex chromosomes are generally derived from a pair of classical type-A chromosomes, and relatively few alternative models have been proposed up to now.1,2 B chromosomes (Bs) are supernumerary and dispensable chromosomes with non-Mendelian inheritance found in many plant and animal species3,4 that have often been considered as selfish genetic elements that behave as genome parasites.5,6 The observation that in some species Bs can be either restricted or predominant in one sex7-14 raised the interesting hypothesis that Bs could play a role in sex determination.15 The characterization of putative B master sex-determining (MSD) genes, however, has not yet been provided to support this hypothesis. Here, in Astyanax mexicanus cavefish originating from Pachón cave, we show that Bs are strongly male predominant. Based on a high-quality genome assembly of a B-carrying male, we characterized the Pachón cavefish B sequence and found that it contains two duplicated loci of the putative MSD gene growth differentiation factor 6b (gdf6b). Supporting its role as an MSD gene, we found that the Pachón cavefish gdf6b gene is expressed specifically in differentiating male gonads, and that its knockout induces male-to-female sex reversal in B-carrying males. This demonstrates that gdf6b is necessary for triggering male sex determination in Pachón cavefish. Altogether these results bring multiple and independent lines of evidence supporting the conclusion that the Pachón cavefish B is a "B-sex" chromosome that contains duplicated copies of the gdf6b gene, which can promote male sex determination in this species.
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9
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Sochorová J, Gálvez F, Matyášek R, Garcia S, Kovařík A. Analyses of the Updated "Animal rDNA Loci Database" with an Emphasis on Its New Features. Int J Mol Sci 2021; 22:11403. [PMID: 34768834 DOI: 10.3390/ijms222111403] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/17/2021] [Accepted: 10/20/2021] [Indexed: 11/17/2022] Open
Abstract
We report on a major update to the animal rDNA loci database, which now contains cytogenetic information for 45S and 5S rDNA loci in more than 2600 and 1000 species, respectively. The data analyses show the following: (i) A high variability in 5S and 45S loci numbers, with both showing 50-fold or higher variability. However, karyotypes with an extremely high number of loci were rare, and medians generally converged to two 5S sites and two 45S rDNA sites per diploid genome. No relationship was observed between the number of 5S and 45S loci. (ii) The position of 45S rDNA on sex chromosomes was relatively frequent in some groups, particularly in arthropods (14% of karyotypes). Furthermore, 45S rDNA was almost exclusively located in microchromosomes when these were present (in birds and reptiles). (iii) The proportion of active NORs (positively stained with silver staining methods) progressively decreased with an increasing number of 45S rDNA loci, and karyotypes with more than 12 loci showed, on average, less than 40% of active loci. In conclusion, the updated version of the database provides some new insights into the organization of rRNA genes in chromosomes. We expect that its updated content will be useful for taxonomists, comparative cytogeneticists, and evolutionary biologists.
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10
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Huang YH, Lin TC, Chiou WY, Cheng YM. The r-X1 deletion induces terminal deficiencies in the maize B chromosome. Chromosome Res 2021. [PMID: 34480269 DOI: 10.1007/s10577-021-09671-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 10/20/2022]
Abstract
In addition to causing the nondisjunction of maize B and normal A chromosomes at the second megaspore division during embryo sac development, the r-X1 deletion results in terminal deficiencies (TDs) in various A chromosomal arms, but whether the r-X1 deletion also induces TDs of the maize B chromosome remains unknown. To answer this question, the chromosomal composition in the r-X1-containing progeny of r-X1/R-r female parents carrying two standard B chromosomes was determined. Nine of 104 (8.7%) examined kernels contained a smaller telocentric B chromosome, and one of these (designated Bdef-1) was further identified as a TD with a breakpoint in the third distal heterochromatic region of the B chromosome. Thus, the results indicated that the r-X1 deletion could also induce TDs of the maize B chromosome during megaspore divisions. The Bdef-1 chromosome lacked nondisjunctional behavior, and this behavior was restored by the presence of the B chromosome in the cell. A transmission analysis of the Bdef-1 chromosome revealed that loss of the distal portion of the B chromosome reduced female but not male transmission of the B chromosome. Furthermore, the Bdef-1 chromosome was used to more finely map B-derived miRNA genes on the B chromosome. Our results indicate that the r-X1 deletion results in TDs of the B chromosome in maize, and the r-X1 deletion system can thus be used to generate a series of terminally truncated B chromosomes that may be used to map features of the B chromosome, including genes and properties related to B chromosome functions.
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11
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Dos Santos LP, Francisco CM, Campos Júnior EO, Castro JP, Utsunomia R, Morelli S, Porto-Foresti F, Foresti F, Artoni RF. Chromosomal Instability and Origin of B Chromosomes in the Amazonian Glass Tetra Moenkhausia oligolepis (Günther, 1864) (Characiformes, Characidae). Cytogenet Genome Res 2021; 161:249-256. [PMID: 34433167 DOI: 10.1159/000517091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/28/2021] [Indexed: 11/19/2022] Open
Abstract
B chromosomes occur in different species of the small characid fishes of the genus Moenkhausia. These supernumerary elements, that do not recombine with chromosomes of the standard A complement and follow their own evolutionary mechanism vary in number, morphology, and distribution. Here, we show karyotypic data of individuals of 2 populations of Moenkhausia oligolepis of the Brazilian Amazon (Pedro Correia and Taboquinha streams, Tocantins river basin), both with a diploid number of 50 chromosomes and karyotypic formula of 10m + 32sm + 8a. In addition to the normal complement, we also observed the occurrence of B chromosomes in the 2 populations with intra- and interindividual variation ranging from 0 to 10 Bs, independent of sex. The C-banding pattern evidenced heterochromatic blocks located mainly in the pericentromeric region of the chromosomes, while the B chromosomes appeared euchromatic. Silver-stained nucleolus organizer regions were identified in multiples sites, and some of these blocks were positive when stained with chromomycin A3. The karyotype analysis and the application of whole-chromosome painting in populations of M. oligolepis reinforce the conservation of the basal diploid number for the genus, as well as the evolutionary tendency in these fishes to carry B chromosomes. Both populations turned out to be in different stages of stability and expansion of their B chromosomes. We further suggest that the origin of these chromosomes is due to the formation of isochromosomes. Here, we identified a pair of complement A chromosomes involved in this process.
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Affiliation(s)
| | - Carine M Francisco
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Brazil
| | - Edimar O Campos Júnior
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Brazil
| | - Jonathan P Castro
- Post-Graduate Program in Evolutionary Biology, Department of Structural, Molecular and Genetic Biology, State University of Ponta Grossa, Ponta Grossa, Brazil
| | - Ricardo Utsunomia
- Department of Genetics, Institute of Biological and Health Sciences, ICBS, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Sandra Morelli
- Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Brazil
| | - Fábio Porto-Foresti
- Department of Biological Sciences, Faculty of Sciences, Paulista State University (UNESP), Bauru, Brazil
| | - Fausto Foresti
- Department of Structural and Functional Biology, Botucatu Biosciences Institute, Paulista State University (UNESP), Botucatu, Brazil
| | - Roberto F Artoni
- Post-Graduate Program in Evolutionary Biology, Department of Structural, Molecular and Genetic Biology, State University of Ponta Grossa, Ponta Grossa, Brazil
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12
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Lewis JJ, Cicconardi F, Martin SH, Reed RD, Danko CG, Montgomery SH. The Dryas iulia Genome Supports Multiple Gains of a W Chromosome from a B Chromosome in Butterflies. Genome Biol Evol 2021; 13:evab128. [PMID: 34117762 PMCID: PMC8290107 DOI: 10.1093/gbe/evab128] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2021] [Indexed: 12/17/2022] Open
Abstract
In butterflies and moths, which exhibit highly variable sex determination mechanisms, the homogametic Z chromosome is deeply conserved and is featured in many genome assemblies. The evolution and origin of the female W sex chromosome, however, remains mostly unknown. Previous studies have proposed that a ZZ/Z0 sex determination system is ancestral to Lepidoptera, and that W chromosomes may originate from sex-linked B chromosomes. Here, we sequence and assemble the female Dryas iulia genome into 32 highly contiguous ordered and oriented chromosomes, including the Z and W sex chromosomes. We then use sex-specific Hi-C, ATAC-seq, PRO-seq, and whole-genome DNA sequence data sets to test if features of the D. iulia W chromosome are consistent with a hypothesized B chromosome origin. We show that the putative W chromosome displays female-associated DNA sequence, gene expression, and chromatin accessibility to confirm the sex-linked function of the W sequence. In contrast with expectations from studies of homologous sex chromosomes, highly repetitive DNA content on the W chromosome, the sole presence of domesticated repetitive elements in functional DNA, and lack of sequence homology with the Z chromosome or autosomes is most consistent with a B chromosome origin for the W, although it remains challenging to rule out extensive sequence divergence. Synteny analysis of the D. iulia W chromosome with other female lepidopteran genome assemblies shows no homology between W chromosomes and suggests multiple, independent origins of the W chromosome from a B chromosome likely occurred in butterflies.
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Affiliation(s)
- James J Lewis
- Baker Institute for Animal Health, Cornell University, Ithaca, New York, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Francesco Cicconardi
- School of Biological Sciences, University of Bristol, United Kingdom
- Department of Zoology, University of Cambridge, United Kingdom
| | - Simon H Martin
- Institute of Evolutionary Biology, University of Edinburgh, United Kingdom
| | - Robert D Reed
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Charles G Danko
- Baker Institute for Animal Health, Cornell University, Ithaca, New York, USA
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Kuchta-Gładysz M, Wójcik E, Grzesiakowska A, Rymuza K, Szeleszczuk O. Chromosomal Instability at Fragile Sites in Blue Foxes, Silver Foxes, and Their Interspecific Hybrids. Animals (Basel) 2021; 11:ani11061743. [PMID: 34207981 PMCID: PMC8230692 DOI: 10.3390/ani11061743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/29/2022] Open
Abstract
Simple Summary The paper describes the karyotypes of blue and silver foxes and their hybrids, in terms of the numbers of A and B chromosomes and the frequency of fragile sites on chromosomes. Genome stability in these species is affected by Robertson translocations in the karyotype of the blue fox and by B chromosomes in the silver fox. The fragile sites assay was used as a biomarker to assess genome stability in foxes. This test enables the identification of breaks, chromatid gaps, and deletions. In healthy individuals, the number of these instabilities remains low. The test can be used to select individuals with the most stable genome for breeding of blue and silver foxes. The fewer an individual’s susceptible sites, the more likely it is to have good reproductive performance. This factor is extremely important in the case of blue foxes, which are an endangered species. Abstract A cytogenetic assay based on fragile sites (FS) enables the identification of breaks, chromatid gaps, and deletions. In healthy individuals, the number of these instabilities remains low. Genome stability in these species is affected by Robertsonian translocations in the karyotype of the blue fox and by B chromosomes in the silver fox. The aims of the study were to characterise the karyotype of blue foxes, silver foxes, and their hybrids and to identify chromosomal fragile sites used to evaluate genome stability. The diploid number of A chromosomes in blue foxes ranged from 48 to 50, while the number of B chromosomes in silver foxes varied from one to four, with a constant number of A chromosomes (2n = 34). In interspecific hybrids, both types of karyotypic variation were identified, with the diploid number of A chromosomes ranging from 40 to 44 and the number of B chromosomes varying from 0 to 3. The mean frequency of FS in foxes was 4.06 ± 0.19: 4.61 ± 0.37 in blue foxes, 3.46 ± 0.28 in silver foxes, and 4.12 ± 0.22 in hybrids. A relationship was identified between an increased number of A chromosomes in the karyotype of the hybrids and the frequency of chromosomal breaks. The FS assay was used as a biomarker for the evaluation of genomic stability in the animals in the study.
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Affiliation(s)
- Marta Kuchta-Gładysz
- Department of Animal Reproduction, Anatomy and Genomics, Faculty of Animal Sciences, University of Agriculture in Krakow, ul. Mickiewicza 24/28, 30-059 Kraków, Poland; (M.K.-G.); (A.G.); (O.S.)
| | - Ewa Wójcik
- Institute of Animal Science and Fisheries, Faculty of Agrobioengineering and Animal Husbandry, Siedlce University of Natural Sciences and Humanities, ul. Prusa 14, 08-110 Siedlce, Poland
- Correspondence:
| | - Anna Grzesiakowska
- Department of Animal Reproduction, Anatomy and Genomics, Faculty of Animal Sciences, University of Agriculture in Krakow, ul. Mickiewicza 24/28, 30-059 Kraków, Poland; (M.K.-G.); (A.G.); (O.S.)
| | - Katarzyna Rymuza
- Institute of Agriculture and Horticulture, Faculty of Agrobioengineering and Animal Husbandry, Siedlce University of Natural Sciences and Humanities, ul. Prusa 14, 08-110 Siedlce, Poland;
| | - Olga Szeleszczuk
- Department of Animal Reproduction, Anatomy and Genomics, Faculty of Animal Sciences, University of Agriculture in Krakow, ul. Mickiewicza 24/28, 30-059 Kraków, Poland; (M.K.-G.); (A.G.); (O.S.)
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14
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Blavet N, Yang H, Su H, Solanský P, Douglas RN, Karafiátová M, Šimková L, Zhang J, Liu Y, Hou J, Shi X, Chen C, El-Walid M, McCaw ME, Albert PS, Gao Z, Zhao C, Ben-Zvi G, Glick L, Kol G, Shi J, Vrána J, Šimková H, Lamb JC, Newton K, Dawe RK, Doležel J, Ji T, Baruch K, Cheng J, Han F, Birchler JA, Bartoš J. Sequence of the supernumerary B chromosome of maize provides insight into its drive mechanism and evolution. Proc Natl Acad Sci U S A 2021; 118:e2104254118. [PMID: 34088847 DOI: 10.1073/pnas.2104254118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
B chromosomes are enigmatic elements in thousands of plant and animal genomes that persist in populations despite being nonessential. They circumvent the laws of Mendelian inheritance but the molecular mechanisms underlying this behavior remain unknown. Here we present the sequence, annotation, and analysis of the maize B chromosome providing insight into its drive mechanism. The sequence assembly reveals detailed locations of the elements involved with the cis and trans functions of its drive mechanism, consisting of nondisjunction at the second pollen mitosis and preferential fertilization of the egg by the B-containing sperm. We identified 758 protein-coding genes in 125.9 Mb of B chromosome sequence, of which at least 88 are expressed. Our results demonstrate that transposable elements in the B chromosome are shared with the standard A chromosome set but multiple lines of evidence fail to detect a syntenic genic region in the A chromosomes, suggesting a distant origin. The current gene content is a result of continuous transfer from the A chromosomal complement over an extended evolutionary time with subsequent degradation but with selection for maintenance of this nonvital chromosome.
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Ma W, Liu Z, Beier S, Houben A, Carpentier S. Identification of rye B chromosome-associated peptides by mass spectrometry. New Phytol 2021; 230:2179-2185. [PMID: 33503271 DOI: 10.1111/nph.17238] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
B chromosomes (Bs) are supernumerary dispensable components of the standard genome (A chromosomes, As) that have been found in many eukaryotes. So far, it is unkown whether the B-derived transcripts translate to proteins or if the host proteome is changed due to the presence of Bs. Comparative mass spectrometry was performed using the protein samples isolated from shoots of rye plants with and without Bs. We aimed to identify B-associated peptides and analyzed the effects of Bs on the total proteome. Our comparative proteome analysis demonstrates that the presence of rye Bs affects the total proteome including different biological function processes. We found 319 of 16 776 quantified features in at least three out of five +B plants but not in 0B plants; 31 of 319 features were identified as B-associated peptide features. According to our data mining, one B-specific protein fragment showed similarity to a glycine-rich RNA binding protein which differed from its A-paralogue by two amino acid insertions. Our result represents a milestone in B chromosome research, because this is the first report to demonstrate the existence of Bs changing the proteome of the host.
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Affiliation(s)
- Wei Ma
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, China
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, Stadt Seeland, 06466, Germany
| | - ZhaoJun Liu
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, Stadt Seeland, 06466, Germany
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, China
- School of Life Sciences Life, Science Center Weihenstephan, Crop Physiology, Technical University Munich, Alte Akademie 12, Freising, 85354, Germany
| | - Sebastian Beier
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, Stadt Seeland, 06466, Germany
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, Stadt Seeland, 06466, Germany
| | - Sebastien Carpentier
- Department of Biosystems, KU Leuven, Willem Decroylaan 42, 2455-3001 Leuven, Belgium
- SYBIOMA, KULeuven, Herestraat 49, Leuven, 3000, Belgium
- Genetic Resources, Bioversity International, Willem Decroylaan 42, 2455-3001 Leuven, Belgium
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16
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Peterson SC, Samuelson KB, Hanlon SL. Multi-Scale Organization of the Drosophila melanogaster Genome. Genes (Basel) 2021; 12:817. [PMID: 34071789 PMCID: PMC8228293 DOI: 10.3390/genes12060817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 12/16/2022] Open
Abstract
Interphase chromatin, despite its appearance, is a highly organized framework of loops and bends. Chromosomes are folded into topologically associating domains, or TADs, and each chromosome and its homolog occupy a distinct territory within the nucleus. In Drosophila, genome organization is exceptional because homologous chromosome pairing is in both germline and somatic tissues, which promote interhomolog interactions such as transvection that can affect gene expression in trans. In this review, we focus on what is known about genome organization in Drosophila and discuss it from TADs to territory. We start by examining intrachromosomal organization at the sub-chromosome level into TADs, followed by a comprehensive analysis of the known proteins that play a key role in TAD formation and boundary establishment. We then zoom out to examine interhomolog interactions such as pairing and transvection that are abundant in Drosophila but rare in other model systems. Finally, we discuss chromosome territories that form within the nucleus, resulting in a complete picture of the multi-scale organization of the Drosophila genome.
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Affiliation(s)
| | | | - Stacey L. Hanlon
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; (S.C.P.); (K.B.S.)
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17
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Chueca LJ, Kochmann J, Schell T, Greve C, Janke A, Pfenninger M, Klimpel S. De novo Genome Assembly of the Raccoon Dog ( Nyctereutes procyonoides). Front Genet 2021; 12:658256. [PMID: 33995489 PMCID: PMC8117329 DOI: 10.3389/fgene.2021.658256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022] Open
Affiliation(s)
- Luis J Chueca
- LOEWE-Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberg Nature Research Society, Frankfurt am Main, Germany.,Department of Zoology and Animal Cell Biology, University of the Basque Country (UPV-EHU), Vitoria-Gasteiz, Spain
| | - Judith Kochmann
- LOEWE-Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberg Nature Research Society, Frankfurt am Main, Germany.,Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
| | - Tilman Schell
- LOEWE-Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberg Nature Research Society, Frankfurt am Main, Germany
| | - Carola Greve
- LOEWE-Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberg Nature Research Society, Frankfurt am Main, Germany
| | - Axel Janke
- LOEWE-Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberg Nature Research Society, Frankfurt am Main, Germany.,Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany.,Institute for Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, Germany
| | - Markus Pfenninger
- LOEWE-Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberg Nature Research Society, Frankfurt am Main, Germany.,Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany.,Institute of Organismic and Molecular Evolution, Faculty of Biology, Johannes Gutenberg University, Mainz, Germany
| | - Sven Klimpel
- LOEWE-Centre for Translational Biodiversity Genomics (LOEWE-TBG), Senckenberg Nature Research Society, Frankfurt am Main, Germany.,Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany.,Institute for Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, Germany
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18
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Camacho JPM, Ruiz-Ruano FJ, López-León MD, Cabrero J. Satellite DNA Is an Inseparable Fellow Traveler of B Chromosomes. Prog Mol Subcell Biol 2021; 60:85-102. [PMID: 34386873 DOI: 10.1007/978-3-030-74889-0_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Next-Generation Sequencing (NGS) has revealed that B chromosomes in several species are enriched in repetitive DNA, mostly satellite DNA (satDNA). This raises the question of whether satDNA is important to B chromosomes for functional reasons or else its abundance on Bs is simply a consequence of properties of B chromosomes such as their dispensability and late replication. Here we review current knowledge in this respect and contextualize it within the frame of practical difficulties to perform this kind of research, the most important being the absence of good full genome sequencing for B-carrying species, which is an essential requisite to ascertain the intragenomic origin of B chromosomes. Our review analysis on 16 species revealed that 38% of them showed B-specific satDNAs whereas only one of them (6%) carried an inter-specifically originated B chromosome. This shows that B-specific satDNA families can eventually evolve in intraspecifically arisen B chromosomes. Finally, the possibility of satDNA accumulation on B chromosomes for functional reasons is exemplified by B chromosomes in rye, as they contain B-specific satDNAs which are transcribed and occupy chromosome locations where they might facilitate the kind of drive shown by this B chromosome during pollen grain mitosis.
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19
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Boudichevskaia A, Ruban A, Thiel J, Fiebig A, Houben A. Tissue-Specific Transcriptome Analysis Reveals Candidate Transcripts Associated with the Process of Programmed B Chromosome Elimination in Aegilops speltoides. Int J Mol Sci 2020; 21:ijms21207596. [PMID: 33066598 PMCID: PMC7593951 DOI: 10.3390/ijms21207596] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 11/30/2022] Open
Abstract
Some eukaryotes exhibit dramatic genome size differences between cells of different organs, resulting from programmed elimination of chromosomes. Here, we present the first transcriptome analysis of programmed chromosome elimination using laser capture microdissection (LCM)-based isolation of the central meristematic region of Aegilops speltoides embryos where B chromosome (B) elimination occurs. The comparative RNA-seq analysis of meristematic cells of embryos with (Bplus) and without Bs (B0) allowed the identification of 14,578 transcript isoforms (35% out of 41,615 analyzed transcript isoforms) that are differentially expressed during the elimination of Bs. A total of 2908 annotated unigenes were found to be up-regulated in Bplus condition. These genes are either associated with the process of B chromosome elimination or with the presence of B chromosomes themselves. GO enrichment analysis categorized up-regulated transcript isoforms into 27 overrepresented terms related to the biological process, nine terms of the molecular function aspect and three terms of the cellular component category. A total of 2726 annotated unigenes were down-regulated in Bplus condition. Based on strict filtering criteria, 341 B-unique transcript isoforms could be identified in central meristematic cells, of which 70 were functionally annotated. Beside others, genes associated with chromosome segregation, kinetochore function and spindle checkpoint activity were retrieved as promising candidates involved in the process of B chromosome elimination.
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Affiliation(s)
- Anastassia Boudichevskaia
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, 06466 OT Gatersleben, Germany; (A.R.); (J.T.); (A.F.)
- KWS SAAT SE & Co. KGaA, 37574 Einbeck, Germany
- Correspondence: (A.B.); (A.H.)
| | - Alevtina Ruban
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, 06466 OT Gatersleben, Germany; (A.R.); (J.T.); (A.F.)
- KWS SAAT SE & Co. KGaA, 37574 Einbeck, Germany
| | - Johannes Thiel
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, 06466 OT Gatersleben, Germany; (A.R.); (J.T.); (A.F.)
| | - Anne Fiebig
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, 06466 OT Gatersleben, Germany; (A.R.); (J.T.); (A.F.)
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Seeland, 06466 OT Gatersleben, Germany; (A.R.); (J.T.); (A.F.)
- Correspondence: (A.B.); (A.H.)
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20
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Shams I, Raskina O. Supernumerary B Chromosomes and Plant Genome Changes: A Snapshot of Wild Populations of Aegilops speltoides Tausch ( Poaceae, Triticeae). Int J Mol Sci 2020; 21:ijms21113768. [PMID: 32466617 PMCID: PMC7312783 DOI: 10.3390/ijms21113768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/20/2020] [Accepted: 05/22/2020] [Indexed: 01/12/2023] Open
Abstract
In various eukaryotes, supernumerary B chromosomes (Bs) are an optional genomic component that affect their integrity and functioning. In the present study, the impact of Bs on the current changes in the genome of goatgrass, Aegilops speltoides, was addressed. Individual plants from contrasting populations with and without Bs were explored using fluorescence in situ hybridization. In parallel, abundances of the Ty1-copia, Ty3-gypsy, and LINE retrotransposons (TEs), and the species-specific Spelt1 tandem repeat (TR) in vegetative and generative spike tissues were estimated by real-time quantitative PCR. The results revealed: (i) ectopic associations between Bs and the regular A chromosomes, and (ii) cell-specific rearrangements of Bs in both mitosis and microgametogenesis. Further, the copy numbers of TEs and TR varied significantly between (iii) genotypes and (iv) different spike tissues in the same plant(s). Finally, (v) in plants with and without Bs from different populations, genomic abundances and/or copy number dynamics of TEs and TR were similar. These findings indicate that fluctuations in TE and TR copy numbers are associated with DNA damage and repair processes during cell proliferation and differentiation, and ectopic recombination is one of the mechanisms by which Bs play a role in genome changes.
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Abstract
Chromosome spreads are important for complex molecular cytogenetic studies. An adequate chromosome spreading method for identification and isolation of the maize B chromosome, however, has not been reported. We used the maize inbred lines, B73 and Mo17, the hybrid YD08 line and the landrace DP76 to develop an optimized chromosome spreading method. We investigated the effects of four treatment factors on the quality of metaphase chromosome spreads using a factorial analysis of variance. Optimal conditions for metaphase spreading were identified using regression analysis based on multifactor orthogonal design of four treatment factors with five levels for each factor. We developed optimal conditions for metaphase spreading as follows: nitrous oxide treatment for 2 h, glacial acetic acid fixation for 2 h, enzyme hydrolysis for 6.0 h, and a drop height of 35 cm for cell suspension. We obtained high quality metaphase chromosome spreads with large metaphase areas, large numbers of chromosomes, few chromosome overlaps and high frequency of intact metaphases. Our optimized drop-slide procedure was markedly better than the traditional flame smear technique. We identified 487 B chromosomes in three forms from maize landraces from Southwest China. We found no relation between the C-band number and B chromosome. Single B chromosomes also were isolated directly from a metaphase chromosome drop-slide using a micromanipulator. Our optimized method provides a simple, efficient and reproducible procedure for preparing high quality plant chromosome spreads.
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Affiliation(s)
- Qilun Yao
- Department of Life Sciences, Yangtze Normal University, Fuling 408100, P. R. China.,Centre for Green Development and Collaborative Innovation in Wuling Mountain Region, Yangtze Normal University, Fuling, 408100, P. R. China
| | - Jian Gao
- Department of Life Sciences, Yangtze Normal University, Fuling 408100, P. R. China.,Centre for Green Development and Collaborative Innovation in Wuling Mountain Region, Yangtze Normal University, Fuling, 408100, P. R. China
| | - Fabo Chen
- Department of Life Sciences, Yangtze Normal University, Fuling 408100, P. R. China.,Centre for Green Development and Collaborative Innovation in Wuling Mountain Region, Yangtze Normal University, Fuling, 408100, P. R. China
| | - Wenbo Li
- Department of Life Sciences, Yangtze Normal University, Fuling 408100, P. R. China.,Centre for Green Development and Collaborative Innovation in Wuling Mountain Region, Yangtze Normal University, Fuling, 408100, P. R. China
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Hong ZJ, Xiao JX, Peng SF, Lin YP, Cheng YM. Novel B-chromosome-specific transcriptionally active sequences are present throughout the maize B chromosome. Mol Genet Genomics 2020; 295:313-25. [PMID: 31729549 DOI: 10.1007/s00438-019-01623-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/04/2019] [Indexed: 10/25/2022]
Abstract
Supernumerary B chromosomes are dispensable parts of the nuclear genome and occur in all eukaryotic groups. They differ from the normal A chromosomes in morphology, genetic behavior, and inheritance. Because they are nonessential for individual development, B chromosomes are considered to be genetically inert and to lack functional genes. However, the maize B chromosome carries control elements that direct its behavior and affects A chromosomes during cell division. Therefore, the maize B chromosome might contain genic regions that differ from the genic regions of A chromosomes. Yet, only a few B-specific transcript sequences have been isolated. To identify more B-specific transcriptionally active sequences, we constructed de novo transcriptome assemblies for maize B73 inbred lines with 0B (+0B) and 2B (+2B). Comparative analysis of the B73 + 0B and B73 + 2B assemblies revealed that unigenes annotated to 201 gene ontology terms were differentially expressed. Using RT-PCR analysis of novel transcript sequences specific to B73 + 2B, we identified 32 novel B-related transcript sequences, and most sequences showed consistent B-specific transcription in different inbred lines. Moreover, 20 of those novel B-related transcript sequences were further confirmed to be located only on the B chromosome by genomic PCR analysis. A total of 19 novel B-specific transcript sequences were mapped to various positions along the B chromosome using B-10L translocations. Taken together, our results suggest that the maize B chromosome indeed affects the expression of A-located genes and that a substantial amount of novel B-specific transcriptionally active sequences are present throughout the maize B chromosome. Therefore, the maize B chromosome seems not to be genetically inert.
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Huang YH, Peng SF, Lin YP, Cheng YM. The maize B chromosome is capable of expressing microRNAs and altering the expression of microRNAs derived from A chromosomes. Chromosome Res 2019; 28:129-138. [PMID: 31712937 DOI: 10.1007/s10577-019-09620-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 11/30/2022]
Abstract
Supernumerary B chromosomes (Bs) are nonessential chromosomes that are considered genetically inert. However, the maize B carries control elements that direct its behavior, such as that of nondisjunction, during the second pollen mitosis, and affects normal A chromosomes during cell division. Recently, the maize B has been found to contain transcriptionally active sequences and to affect the transcription of genes on A chromosomes. To better understand the regulatory mechanisms underlying the maize B, we constructed two small RNA libraries from maize B73 inbred lines with and without Bs. The sequencing results revealed that 18 known microRNAs (miRNAs) were significantly differentially expressed in response to the presence of the B, and most target mRNAs were characterized as transcription factors. Moreover, three novel B-derived miRNAs were identified via stem-loop reverse transcriptase-polymerase chain reaction (RT-PCR)-based analysis, and all showed consistent B-specific expression in almost all analyzed inbred lines and in all tissue types, including leaves, roots, and pollen grains. By the use of B-10L translocations, the three B-derived miRNAs were mapped to specific B regions. The results from this study suggest that the maize B can express miRNAs and affect the expression of A-derived miRNAs, which could regulate the expression of A-located genes.
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Affiliation(s)
- Yen-Hua Huang
- Department of Agronomy, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, 402, Taiwan
| | - Shu-Fen Peng
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
| | - Yao-Pin Lin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Ya-Ming Cheng
- Department of Agronomy, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, 402, Taiwan.
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Dhar MK, Kour J, Kaul S. Origin, Behaviour, and Transmission of B Chromosome with Special Reference to Plantago lagopus. Genes (Basel) 2019; 10:E152. [PMID: 30781667 PMCID: PMC6410184 DOI: 10.3390/genes10020152] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 11/30/2022] Open
Abstract
B chromosomes have been reported in many eukaryotic organisms. These chromosomes occur in addition to the standard complement of a species. Bs do not pair with any of the A chromosomes and they have generally been considered to be non-essential and genetically inert. However, due to tremendous advancements in the technologies, the molecular composition of B chromosomes has been determined. The sequencing data has revealed that B chromosomes have originated from A chromosomes and they are rich in repetitive elements. In our laboratory, a novel B chromosome was discovered in Plantago lagopus. Using molecular cytogenetic techniques, the B chromosome was found to be composed of ribosomal DNA sequences. However, further characterization of the chromosome using next generation sequencing (NGS) etc. revealed that the B chromosome is a mosaic of sequences derived from A chromosomes, 5S ribosomal DNA (rDNA), 45S rDNA, and various types of repetitive elements. The transmission of B chromosome through the female sex track did not follow the Mendelian principles. The chromosome was found to have drive due to which it was perpetuating in populations. The present paper attempts to summarize the information on nature, transmission, and origin of B chromosomes, particularly the current status of our knowledge in P. lagopus.
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Affiliation(s)
- Manoj K Dhar
- Genome Research Laboratory, School of Biotechnology, University of Jammu, Jammu-180006, India.
| | - Jasmeet Kour
- Genome Research Laboratory, School of Biotechnology, University of Jammu, Jammu-180006, India.
| | - Sanjana Kaul
- Genome Research Laboratory, School of Biotechnology, University of Jammu, Jammu-180006, India.
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Albert PS, Zhang T, Semrau K, Rouillard JM, Kao YH, Wang CR, Danilova TV, Jiang J, Birchler JA. Whole-chromosome paints in maize reveal rearrangements, nuclear domains, and chromosomal relationships. Proc Natl Acad Sci U S A 2019; 116:1679-85. [PMID: 30655344 DOI: 10.1073/pnas.1813957116] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Whole-chromosome painting probes were developed for each of the 10 chromosomes of maize by producing amplifiable libraries of unique sequences of oligonucleotides that can generate labeled probes through transcription reactions. These paints allow identification of individual homologous chromosomes for many applications as demonstrated in somatic root tip metaphase cells, in the pachytene stage of meiosis, and in interphase nuclei. Several chromosomal aberrations were examined as proof of concept for study of various rearrangements using probes that cover the entire chromosome and that label diverse varieties. The relationship of the supernumerary B chromosome and the normal chromosomes was examined with the finding that there is no detectable homology between any of the normal A chromosomes and the B chromosome. Combined with other chromosome-labeling techniques, a complete set of whole-chromosome oligonucleotide paints lays the foundation for future studies of the structure, organization, and evolution of genomes.
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Navarro-Domínguez B, Martín-Peciña M, Ruiz-Ruano FJ, Cabrero J, Corral JM, López-León MD, Sharbel TF, Camacho JPM. Gene expression changes elicited by a parasitic B chromosome in the grasshopper Eyprepocnemis plorans are consistent with its phenotypic effects. Chromosoma 2019; 128:53-67. [PMID: 30617552 DOI: 10.1007/s00412-018-00689-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 01/16/2023]
Abstract
Parasitism evokes adaptive physiological changes in the host, many of which take place through gene expression changes. This response can be more or less local, depending on the organ or tissue affected by the parasite, or else systemic when the parasite affects the entire host body. The most extreme of the latter cases is intragenomic parasitism, where the parasite is present in all host nuclei as any other genomic element. Here, we show the molecular crosstalk between a parasitic chromosome (also named B chromosome) and the host genome, manifested through gene expression changes. The transcriptome analysis of 0B and 1B females of the grasshopper Eyprepocnemis plorans, validated by a microarray experiment performed on four B-lacking and five B-carrying females, revealed changes in gene expression for 188 unigenes being consistent in both experiments. Once discarded B-derived transcripts, there were 46 differentially expressed genes (30 up- and 16 downregulated) related with the adaptation of the host genome to the presence of the parasitic chromosome. Interestingly, the functions of these genes could explain some of the most important effects of B chromosomes, such as nucleotypic effects derived from the additional DNA they represent, chemical defense and detoxification, protein modification and response to stress, ovary function, and regulation of gene expression. Collectively, these changes uncover an intimate host-parasite interaction between A and B chromosomes during crucial steps of gene expression and protein function.
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Habig M, Kema GHJ, Holtgrewe Stukenbrock E. Meiotic drive of female-inherited supernumerary chromosomes in a pathogenic fungus. eLife 2018; 7:e40251. [PMID: 30543518 PMCID: PMC6331196 DOI: 10.7554/elife.40251] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 12/13/2018] [Indexed: 01/03/2023] Open
Abstract
Meiosis is a key cellular process of sexual reproduction that includes pairing of homologous sequences. In many species however, meiosis can also involve the segregation of supernumerary chromosomes, which can lack a homolog. How these unpaired chromosomes undergo meiosis is largely unknown. In this study we investigated chromosome segregation during meiosis in the haploid fungus Zymoseptoria tritici that possesses a large complement of supernumerary chromosomes. We used isogenic whole chromosome deletion strains to compare meiotic transmission of chromosomes when paired and unpaired. Unpaired chromosomes inherited from the male parent as well as paired supernumerary chromosomes in general showed Mendelian inheritance. In contrast, unpaired chromosomes inherited from the female parent showed non-Mendelian inheritance but were amplified and transmitted to all meiotic products. We concluded that the supernumerary chromosomes of Z. tritici show a meiotic drive and propose an additional feedback mechanism during meiosis, which initiates amplification of unpaired female-inherited chromosomes.
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Affiliation(s)
- Michael Habig
- Environmental GenomicsChristian-Albrechts University of KielKielGermany
- Max Planck Institute for Evolutionary BiologyPlönGermany
| | - Gert HJ Kema
- Wageningen Plant ResearchWageningen University and ResearchWageningenThe Netherlands
- Laboratory of PhytopathologyWageningen University and ResearchWageningenThe Netherlands
| | - Eva Holtgrewe Stukenbrock
- Environmental GenomicsChristian-Albrechts University of KielKielGermany
- Max Planck Institute for Evolutionary BiologyPlönGermany
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28
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Hanlon SL, Miller DE, Eche S, Hawley RS. Origin, Composition, and Structure of the Supernumerary B Chromosome of Drosophila melanogaster. Genetics 2018; 210:1197-1212. [PMID: 30249684 PMCID: PMC6283169 DOI: 10.1534/genetics.118.301478] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/23/2018] [Indexed: 01/18/2023] Open
Abstract
The number of chromosomes carried by an individual species is one of its defining characteristics. Some species, however, can also carry supernumerary chromosomes referred to as B chromosomes. B chromosomes were recently identified in a laboratory stock of Drosophila melanogaster-an established model organism with a wealth of genetic and genomic resources-enabling us to subject them to extensive molecular analysis. We isolated the B chromosomes by pulsed-field gel electrophoresis and determined their composition through next-generation sequencing. Although these B chromosomes carry no known euchromatic sequence, they are rich in transposable elements and long arrays of short nucleotide repeats, the most abundant being the uncharacterized AAGAT satellite repeat. Fluorescent in situ hybridization on metaphase chromosome spreads revealed this repeat is located on chromosome 4, strongly suggesting the origin of the B chromosomes is chromosome 4 Cytological and quantitative comparisons of signal intensity between chromosome 4 and the B chromosomes supports the hypothesis that the structure of the B chromosome is an isochromosome. We also report the identification of a new B chromosome variant in a related laboratory stock. This B chromosome has a similar repeat signature as the original but is smaller and much less prevalent. We examined additional stocks with similar genotypes and did not find B chromosomes, but did find these stocks lacked the AAGAT satellite repeat. Our molecular characterization of D. melanogaster B chromosomes is the first step toward understanding how supernumerary chromosomes arise from essential chromosomes and what may be necessary for their stable inheritance.
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Affiliation(s)
- Stacey L Hanlon
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Danny E Miller
- Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, Washington 98105
| | - Salam Eche
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - R Scott Hawley
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160
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29
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Marques A, Klemme S, Houben A. Evolution of Plant B Chromosome Enriched Sequences. Genes (Basel) 2018; 9:genes9100515. [PMID: 30360448 PMCID: PMC6210368 DOI: 10.3390/genes9100515] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/13/2018] [Accepted: 10/18/2018] [Indexed: 01/10/2023] Open
Abstract
B chromosomes are supernumerary chromosomes found in addition to the normal standard chromosomes (A chromosomes). B chromosomes are well known to accumulate several distinct types of repeated DNA elements. Although the evolution of B chromosomes has been the subject of numerous studies, the mechanisms of accumulation and evolution of repetitive sequences are not fully understood. Recently, new genomic approaches have shed light on the origin and accumulation of different classes of repetitive sequences in the process of B chromosome formation and evolution. Here we discuss the impact of repetitive sequences accumulation on the evolution of plant B chromosomes.
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Affiliation(s)
- André Marques
- Laboratory of Genetic Resources, Federal University of Alagoas, Av. Manoel Severino Barbosa, 57309-005 Arapiraca-AL, Brazil.
| | - Sonja Klemme
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, CZ-37005 České Budějovice, Czech Republic.
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466 Gatersleben, Germany.
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Han F, Lamb JC, McCaw ME, Gao Z, Zhang B, Swyers NC, Birchler JA. Meiotic Studies on Combinations of Chromosomes With Different Sized Centromeres in Maize. Front Plant Sci 2018; 9:785. [PMID: 29951076 PMCID: PMC6008422 DOI: 10.3389/fpls.2018.00785] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/23/2018] [Indexed: 05/16/2023]
Abstract
Multiple centromere misdivision derivatives of a translocation between the supernumerary B chromosome and the short arm of chromosome 9 (TB-9Sb) permit investigation of how centromeres of different sizes behave in meiosis in opposition or in competition with each other. In the first analysis, heterozygotes were produced between the normal TB-9Sb and derivatives of it that resulted from centromere misdivision that reduced the amounts of centromeric DNA. These heterozygotes could test whether these drastic differences would result in meiotic drive of the larger chromosome in female meiosis. Cytological determinations of the segregation of large and small centromeres among thousands of progeny of four combinations were made. The recovery of the larger centromere was at a few percent higher frequency in two of four combinations. However, examination of phosphorylated histone H2A-Thr133, a characteristic of active centromeres, showed a lack of correlation with the size of the centromeric DNA, suggesting an expansion of the basal protein features of the kinetochore in two of the three cases despite the reduction in the size of the underlying DNA. In the second analysis, plants containing different sizes of the B chromosome centromere were crossed to plants with TB-9Sb with a foldback duplication of 9S (TB-9Sb-Dp9). In the progeny, plants containing large and small versions of the B chromosome centromere were selected by FISH. A meiotic "tug of war" occurred in hybrid combinations by recombination between the normal 9S and the foldback duplication in those cases in which pairing occurred. Such pairing and recombination produce anaphase I bridges but in some cases the large and small centromeres progressed to the same pole. In one combination, new dicentric chromosomes were found in the progeny. Collectively, the results indicate that the size of the underlying DNA of a centromere does not dramatically affect its segregation properties or its ability to progress to the poles in meiosis potentially because the biochemical features of centromeres adjust to the cellular conditions.
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Affiliation(s)
- Fangpu Han
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Jonathan C. Lamb
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - Morgan E. McCaw
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - Zhi Gao
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - Bing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Nathan C. Swyers
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
| | - James A. Birchler
- Division of Biological Sciences, University of Missouri, Columbia, MO, United States
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Tseng SH, Peng SF, Cheng YM. Analysis of B chromosome nondisjunction induced by the r-X1 deficiency in maize. Chromosome Res 2017; 26:153-162. [PMID: 29159670 DOI: 10.1007/s10577-017-9567-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/08/2017] [Accepted: 11/08/2017] [Indexed: 02/02/2023]
Abstract
The maize B chromosome typically undergoes nondisjunction during the second microspore division. For normal A chromosomes, the r-X1 deficiency in maize can induce nondisjunction during the second megaspore and first microspore divisions. However, it is not known whether the r-X1 deficiency also induces nondisjunction of the maize B chromosome during these cell divisions. To answer this question, chromosome numbers were determined in the progeny of r-X1/R-r female parents carrying two B chromosomes. Some of the r-X1-lacking progeny (21.2%) contained zero or two B chromosomes. However, a much higher percentage of the r-X1-containing progeny (43.4%) exhibited zero or two B chromosomes, but none displayed more than two B chromosomes. Thus, the results indicated that the r-X1 deficiency could also induce nondisjunction of the B chromosome during the second megaspore division; moreover, the B chromosome in itself could undergo nondisjunction during the same division. In addition, pollen grains from plants with two B chromosomes lacking or exhibiting the r-X1 deficiency were compared via pollen fluorescence in situ hybridization (FISH) using a B chromosome-specific probe. The results revealed that the r-X1 deficiency could induce the occurrence of B chromosome nondisjunction during the first microspore division and that the B chromosome in itself could undergo nondisjunction during the same division at a lower frequency. Our data shed more light on the behavior of the maize B chromosome during cell division.
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Affiliation(s)
- Shih-Hsuan Tseng
- Department of Agronomy, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, 402, Taiwan
| | - Shu-Fen Peng
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
| | - Ya-Ming Cheng
- Department of Agronomy, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, 402, Taiwan.
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32
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Ruban A, Schmutzer T, Scholz U, Houben A. How Next-Generation Sequencing Has Aided Our Understanding of the Sequence Composition and Origin of B Chromosomes. Genes (Basel) 2017; 8:E294. [PMID: 29068386 PMCID: PMC5704207 DOI: 10.3390/genes8110294] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/18/2017] [Accepted: 10/24/2017] [Indexed: 12/21/2022] Open
Abstract
Accessory, supernumerary, or-most simply-B chromosomes, are found in many eukaryotic karyotypes. These small chromosomes do not follow the usual pattern of segregation, but rather are transmitted in a higher than expected frequency. As increasingly being demonstrated by next-generation sequencing (NGS), their structure comprises fragments of standard (A) chromosomes, although in some plant species, their sequence also includes contributions from organellar genomes. Transcriptomic analyses of various animal and plant species have revealed that, contrary to what used to be the common belief, some of the B chromosome DNA is protein-encoding. This review summarizes the progress in understanding B chromosome biology enabled by the application of next-generation sequencing technology and state-of-the-art bioinformatics. In particular, a contrast is drawn between a direct sequencing approach and a strategy based on a comparative genomics as alternative routes that can be taken towards the identification of B chromosome sequences.
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Affiliation(s)
- Alevtina Ruban
- Leibniz Institute of Plant Genetics and Crop Plant Research Gatersleben, 06466 Seeland, Germany.
| | - Thomas Schmutzer
- Leibniz Institute of Plant Genetics and Crop Plant Research Gatersleben, 06466 Seeland, Germany.
| | - Uwe Scholz
- Leibniz Institute of Plant Genetics and Crop Plant Research Gatersleben, 06466 Seeland, Germany.
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research Gatersleben, 06466 Seeland, Germany.
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Ruiz-Ruano FJ, Cabrero J, López-León MD, Sánchez A, Camacho JPM. Quantitative sequence characterization for repetitive DNA content in the supernumerary chromosome of the migratory locust. Chromosoma 2017; 127:45-57. [PMID: 28868580 DOI: 10.1007/s00412-017-0644-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 12/23/2022]
Abstract
Repetitive DNA is a major component in most eukaryotic genomes but is ignored in most genome sequencing projects. Here, we report the quantitative composition in repetitive DNA for a supernumerary (B) chromosome, in the migratory locust (Locusta migratoria), by Illumina sequencing of genomic DNA from B-carrying and B-lacking individuals and DNA obtained from a microdissected B chromosome, as well as the physical mapping of some elements. B chromosome DNA of 94.9% was repetitive, in high contrast with the 64.1% of standard (A) chromosomes. B chromosomes are enriched in satellite DNA (satDNA) (65.2% of B-DNA), with a single satellite (LmiSat02-176) comprising 55% of the B. Six satDNAs were visualized by FISH on the B chromosome, and the only A chromosome carrying all these satellites was autosome 9, pointing to this chromosome, along with autosome 8 (which shares histone genes with the B) as putative ancestors of the B chromosome. We found several transposable elements (TEs) showing nucleotidic variation specific to B-carrying individuals, which was also present in B-carrying transcriptomes. Remarkably, an interstitial region of the B chromosome included a 17 kb chimera composed of 29 different TEs, suggesting reiterative TE insertion in this B chromosome region.
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Affiliation(s)
- Francisco J Ruiz-Ruano
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain.
| | - Josefa Cabrero
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain
| | - María Dolores López-León
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain
| | - Antonio Sánchez
- Departamento de Biología Experimental, Universidad de Jaén, Jaén, Spain
| | - Juan Pedro M Camacho
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain
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Milani D, Ramos É, Loreto V, Martí DA, Cardoso AL, de Moraes KCM, Martins C, Cabral-de-Mello DC. The satellite DNA AflaSAT-1 in the A and B chromosomes of the grasshopper Abracris flavolineata. BMC Genet 2017; 18:81. [PMID: 28851268 PMCID: PMC5575873 DOI: 10.1186/s12863-017-0548-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/22/2017] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Satellite DNAs (satDNAs) are organized in repetitions directly contiguous to one another, forming long arrays and composing a large portion of eukaryote genomes. These sequences evolve according to the concerted evolution model, and homogenization of repeats is observed at the intragenomic level. Satellite DNAs are the primary component of heterochromatin, located primarily in centromeres and telomeres. Moreover, satDNA enrichment in specific chromosomes has been observed, such as in B chromosomes, that can provide clues about composition, origin and evolution of this chromosome. In this study, we isolated and characterized a satDNA in A and B chromosomes of Abracris flavolineata by integrating cytogenetic, molecular and genomics approaches at intra- and inter-population levels, with the aim to understand the evolution of satDNA and composition of B chromosomes. RESULTS AflaSAT-1 satDNA was shared with other species and in A. flavolineata, was associated with another satDNA, AflaSAT-2. Chromosomal mapping revealed centromeric blocks variable in size in almost all chromosomes (except pair 11) of A complement for both satDNAs, whereas for B chromosome, only a small centromeric signal occurred. In distinct populations, variable number of AflaSAT-1 chromosomal sites correlated with variability in copy number. Instead of such variability, low sequence diversity was observed in A complement, but monomers from B chromosome were more variable, presenting also exclusive mutations. AflaSAT-1 was transcribed in five tissues of adults in distinct life cycle phases. CONCLUSIONS The sharing of AflaSAT-1 with other species is consistent with the library hypothesis and indicates common origin in a common ancestor; however, AflaSAT-1 was highly amplified in the genome of A. flavolineata. At the population level, homogenization of repeats in distinct populations was documented, but dynamic expansion or elimination of repeats was also observed. Concerning the B chromosome, our data provided new information on the composition in A. flavolineata. Together with previous results, the sequences of heterochromatic nature were not likely highly amplified in the entire B chromosome. Finally, the constitutive transcriptional activity suggests a possible unknown functional role, which should be further investigated.
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Affiliation(s)
- Diogo Milani
- Departamento de Biologia, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, São Paulo CEP 13506-900 Brazil
| | - Érica Ramos
- Departamento de Morfologia, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Botucatu, São Paulo Brazil
| | - Vilma Loreto
- Departamento de Genética, UFPE - Univ Federal de Pernambuco, Centro de Biociências/CB, Recife, Pernambuco Brazil
| | | | - Adauto Lima Cardoso
- Departamento de Morfologia, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Botucatu, São Paulo Brazil
| | | | - Cesar Martins
- Departamento de Morfologia, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Botucatu, São Paulo Brazil
| | - Diogo Cavalcanti Cabral-de-Mello
- Departamento de Biologia, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, São Paulo CEP 13506-900 Brazil
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Abstract
B chromosomes are non-essential components of numerous plant and animal genomes. Because many of these "extra" chromosomes enhance their own transmission in ways that are detrimental to the rest of the genome, they can be thought of as genome parasites. An extreme example is a paternally inherited B chromosome known as paternal sex ratio (PSR), which is found in natural populations of the jewel wasp Nasonia vitripennis. In order to ensure its own propagation, PSR severely biases the wasp sex ratio by converting diploid female-destined embryos into transmitting haploid males. This action occurs at the expense of the other paternally inherited chromosomes, which fail to resolve during the first round of division and are thus eliminated. Recent work has revealed that paternal genome elimination by PSR occurs through the disruption of a number of specific histone post-translational modifications, suggesting a central role for chromatin regulation in this phenomenon. In this review, we describe these recent advances in the light of older ones and in the context of what is currently understood about the molecular mechanisms of targeted genome silencing and elimination in other systems.
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Affiliation(s)
| | - Patrick M. Ferree
- W.M. Keck Science Department, Claremont McKenna College, Pitzer College and Scripps College, ClaremontCA, USA
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36
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Ruiz-Ruano FJ, Cabrero J, López-León MD, Camacho JPM. Satellite DNA content illuminates the ancestry of a supernumerary (B) chromosome. Chromosoma 2017; 126:487-500. [PMID: 27522227 DOI: 10.1007/s00412-016-0611-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/28/2016] [Accepted: 08/02/2016] [Indexed: 12/23/2022]
Abstract
B chromosomes are supernumerary genomic elements most likely derived from the standard (A) chromosomes, whose dispensability has freed their DNA sequences to evolve fast, thus making it difficult to uncover their ancestry. Here, we show the ancestry of a B chromosome in the grasshopper Eumigus monticola by means of the high-throughput analysis of the satellitome, i.e., the whole collection of satellite DNA (satDNA). The satellitome found in this species consists of 27 satDNA families, with monomer length between 5 and 325 nt and A + T content between 42.9 and 83.3 %. Two out of the 20 clustered satDNA families (EmoSat26-41 and EmoSat27-102) were observed only on the B chromosome. The A chromosome carrying the highest number of satDNA families was the megameric S8 (13 families), six of which were also present in the B chromosome, and three of these were exclusive of the S8 and B chromosomes. The absence in the B chromosome of the H3 histone gene cluster (located interstitially on S8) and three satDNA families (located distally on S8) allowed delimiting the possible origin of the B chromosome to the proximal third of the S8 autosome, through a breakpoint between EmoSat11-122 and the H3 cluster. Interestingly, bioinformatic analysis revealed the presence of seeds for the two B-specific satDNAs in the A chromosomes, suggesting their massive amplification in the B chromosome after its origin. Therefore, intraspecifically arisen B chromosomes can harbor DNA sequences apparently being B-specific.
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37
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Huang W, Du Y, Zhao X, Jin W. B chromosome contains active genes and impacts the transcription of A chromosomes in maize (Zea mays L.). BMC Plant Biol 2016; 16:88. [PMID: 27083560 PMCID: PMC4833949 DOI: 10.1186/s12870-016-0775-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/11/2016] [Indexed: 05/03/2023]
Abstract
BACKGROUND The dispensable maize (Zea mays L.) B chromosome is highly heterochromatic and widely believed to be devoid of functional genes. Although low-copy B chromosome causes no obvious phenotype variation, its existence might influence A genome gene expression. Previous studies suggested that B chromosomes are evolved from standard chromosomes; therefore, they might contain genic regions showing homology with A chromosome sequences. RESULTS Our data suggested that maize B chromosome influences the A-genome transcription with stronger effect associated with an increase in copy number of B chromosome. In total 130 differently expressed genes were detected in comparison between with and without B chromosome lines. These differentially expressed genes are mainly involved in cell metabolism and nucleotide binding. Using Starter + B, we amplified ten B chromosome loci with high sequence similarity to A-genome genes. Fluorescence in situ hybridization (FISH) confirmed that at least four ~5 kb-sized genes are located on the B chromosome. In addition, through de novo assembly of the reads not unmapped to maize B73 reference genome together with PCR validation, we found three B-located LTR; in particular, one of them, the 3.2 kb comp75688, is expressed in a B-dosage dependent manner. CONCLUSION We found that in the presence of maize B chromosome, the transcription of A genome genes was altered, with more impact by the increase of the B chromosome number. The B-located transcriptionally active genes showed high similarity to their A-genome homologues, and retrotransposons on B chromosome also have partial homologous to A genome sequences. Our data shed more lights on the genome structure and evolution of the maize B chromosome.
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Affiliation(s)
- Wei Huang
- National Maize Improvement Center of China, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193 China
| | - Yan Du
- National Maize Improvement Center of China, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193 China
| | - Xin Zhao
- National Maize Improvement Center of China, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193 China
| | - Weiwei Jin
- National Maize Improvement Center of China, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193 China
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de A Silva DMZ, Daniel SN, Camacho JPM, Utsunomia R, Ruiz-Ruano FJ, Penitente M, Pansonato-Alves JC, Hashimoto DT, Oliveira C, Porto-Foresti F, Foresti F. Origin of B chromosomes in the genus Astyanax (Characiformes, Characidae) and the limits of chromosome painting. Mol Genet Genomics 2016; 291:1407-18. [PMID: 26984341 DOI: 10.1007/s00438-016-1195-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/02/2016] [Indexed: 11/25/2022]
Abstract
Eukaryote genomes are frequently burdened with the presence of supernumerary (B) chromosomes. Their origin is frequently investigated by chromosome painting, under the hypothesis that sharing the repetitive DNA sequences contained in the painting probes is a sign of common descent. However, the intragenomic mobility of many anonymous DNA sequences contained in these probes (e.g., transposable elements) adds high uncertainty to this conclusion. Here we test the validity of chromosome painting to investigate B chromosome origin by comparing its results for seven B chromosome types in two fish species genus Astyanax, with those obtained (1) by means of the physical mapping of 18S ribosomal DNA (rDNA), H1 histone genes, the As51 satellite DNA and the (AC)15 microsatellite, and (2) by comparing the nucleotide sequence of one of these families (ITS regions from ribosomal DNA) between genomic DNA from B-lacking individuals in both species and the microdissected DNA from two metacentric B chromosomes found in these same species. Intra- and inter-specific painting suggested that all B chromosomes that were assayed shared homologous DNA sequences among them, as well as with a variable number of A chromosomes in each species. This finding would be consistent with a common origin for all seven B chromosomes analyzed. By contrast, the physical mapping of repetitive DNA sequences failed to give support to this hypothesis, as no more than two B-types shared a given repetitive DNA. Finally, sequence analysis of the ITS regions suggested that at least some of the B chromosomes could have had a common origin.
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Affiliation(s)
- Duílio M Z de A Silva
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Junior, s/n, Botucatu, SP, 18618-970, Brazil.
| | - Sandro Natal Daniel
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista, Campus de Bauru., Bauru, SP, 17033-360, Brazil
| | | | - Ricardo Utsunomia
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Junior, s/n, Botucatu, SP, 18618-970, Brazil
| | | | - Manolo Penitente
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista, Campus de Bauru., Bauru, SP, 17033-360, Brazil
| | - José Carlos Pansonato-Alves
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Junior, s/n, Botucatu, SP, 18618-970, Brazil
| | - Diogo Teruo Hashimoto
- CAUNESP, Universidade Estadual Paulista, Campus Jaboticabal, Jaboticabal, SP, 14884-900, Brazil
| | - Claudio Oliveira
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Junior, s/n, Botucatu, SP, 18618-970, Brazil
| | - Fábio Porto-Foresti
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista, Campus de Bauru., Bauru, SP, 17033-360, Brazil
| | - Fausto Foresti
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Junior, s/n, Botucatu, SP, 18618-970, Brazil
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Cheng YM, Feng YR, Lin YP, Peng SF. Cytomolecular characterization and origin of de novo formed maize B chromosome variants. Chromosome Res 2016; 24:183-95. [PMID: 26748511 DOI: 10.1007/s10577-015-9516-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/20/2015] [Accepted: 12/29/2015] [Indexed: 10/22/2022]
Abstract
B chromosomes are dispensable elements that occur in many species, including maize. The maize B chromosome is acrocentric and highly heterochromatic and undergoes nondisjunction during the second pollen mitosis. In this study, we determined the genetic behavior and organization of two naturally occurring B chromosome variants (designated B(ta) and B(tb)). The morphology and genetic behavior of the B(ta) chromosome were similar to those of the typical B chromosome, but the B(ta) chromosome contained a deletion in the first heterochromatin region and had higher transmission frequencies through both male and female parents. The B(tb) chromosome was reduced in size, consisted primarily of heterochromatin, and had a lower transmission frequency. The B(tb) chromosome lacked nondisjunctional behavior, which was restored by the presence of normal B chromosomes in the cell. Furthermore, the B(tb) chromosome contained two centromeric regions, only one of which was active. The organization of these two naturally occurring B chromosome variants was also determined using fluorescence in situ hybridization with B-associated sequences and by amplification of B-specific molecular markers to create possible evolutionary models.
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Affiliation(s)
- Ya-Ming Cheng
- Department of Agronomy, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, 402, Taiwan.
| | - Ying-Ru Feng
- Department of Agronomy, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, 402, Taiwan
| | - Yao-Pin Lin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Shu-Fen Peng
- Department of Biological Science and Technology, China Medical University, Taichung, Taiwan
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Ellis NA, Douglas RN, Jackson CE, Birchler JA, Dawe RK. Generation of a Maize B Centromere Minimal Map Containing the Central Core Domain. G3 (Bethesda) 2015; 5:2857-64. [PMID: 26511496 DOI: 10.1534/g3.115.022889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The maize B centromere has been used as a model for centromere epigenetics and as the basis for building artificial chromosomes. However, there are no sequence resources for this important centromere. Here we used transposon display for the centromere-specific retroelement CRM2 to identify a collection of 40 sequence tags that flank CRM2 insertion points on the B chromosome. These were confirmed to lie within the centromere by assaying deletion breakpoints from centromere misdivision derivatives (intracentromere breakages caused by centromere fission). Markers were grouped together on the basis of their association with other markers in the misdivision series and assembled into a pseudocontig containing 10.1 kb of sequence. To identify sequences that interact directly with centromere proteins, we carried out chromatin immunoprecipitation using antibodies to centromeric histone H3 (CENH3), a defining feature of functional centromeric sequences. The CENH3 chromatin immunoprecipitation map was interpreted relative to the known transmission rates of centromere misdivision derivatives to identify a centromere core domain spanning 33 markers. A subset of seven markers was mapped in additional B centromere misdivision derivatives with the use of unique primer pairs. A derivative previously shown to have no canonical centromere sequences (Telo3-3) lacks these core markers. Our results provide a molecular map of the B chromosome centromere and identify key sequences within the map that interact directly with centromeric histone H3.
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Ferreira-Neto M, Artoni RF, Vicari MR, Moreira-Filho O, Camacho JPM, Bakkali M, de Oliveira C, Foresti F. Three sympatric karyomorphs in the fish Astyanax fasciatus (Teleostei, Characidae) do not seem to hybridize in natural populations. Comp Cytogenet 2012; 6:29-40. [PMID: 24260650 PMCID: PMC3833771 DOI: 10.3897/compcytogen.v6i1.2151] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 01/03/2012] [Indexed: 05/25/2023]
Abstract
Ninety individuals of the characid fish Astyanax fasciatus (Cuvier, 1819) were collected at Água da Madalena stream (Botucatu, São Paulo, Brazil) and analyzed for diploid chromosome number 2n and karyotype composition as well as for the chromosomal location of the 5S and 18S ribosomal DNA (rDNA). Whereas no chromosome differences were associated with sex, three different karyomorphs with diploid chromosome numbers 2n=46, 2n=48 and 2n=50 were found. No intermediate 2n numbers were discovered. The 2n=50 karyomorph showed some differences in 18S rDNA location compared to the two other karyomorphs. Finally, all specimens with the 2n=46 karyomorph showed the presence of a partly heterochromatic macro supernumerary chromosome, which was absent in all individuals with the two other karyomorphs. All these results suggest that indviduals of the three different karyomorphs are not likely to hybridize in the examined populations. Our findings strongly suggest the presence of three separate species (sensu biological species concept) easily diagnosed on the basis of differences in the diploid chromosome numbers and other chromosomal markers.
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Affiliation(s)
- Maressa Ferreira-Neto
- Departmento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Jr, Botucatu, São Paulo, Brazil
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de Brito Marthe J, Pompolo SDG, de Oliveira Campos LA, Salomão TMF, Tavares MG. Cytogenetic characterization of Partamona cupira (Hymenoptera, Apidae) by fluorochromes. Genet Mol Biol 2010; 33:253-5. [PMID: 21637478 PMCID: PMC3036866 DOI: 10.1590/s1415-47572010005000029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 11/03/2009] [Indexed: 11/22/2022] Open
Abstract
Four colonies of the stingless bee Partamona cupira (Hymenoptera: Apidae) were cytogenetically analyzed using conventional staining and the fluorochromes CMA3 e DAPI. The females have 2n = 34 chromosomes (2K = 32
M¯+2
A¯). Some females, however, presented an additional large B acrocentric chromosome, to a total of 2n = 35. Chromosome B and the chromosomal pairs 2, 9 and 10 showed CMA 3+ bands, indicating an excess of CG base-pairs. A clear association was verified between the P. helleri B chromosome SCAR marker and the presence of a B chromosome in P. cupira. The data obtained suggests that B chromosomes in P. helleri and P. cupira share a common origin.
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