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Dos Santos Guimarães A, Maciel LAM, de Souza MFB, Rodrigues LRR. Karyotypic and Molecular Analysis of Pterygoplichthys pardalis (Castelnau 1855) from the Lower Amazon River. Animals (Basel) 2023; 13:ani13091533. [PMID: 37174570 PMCID: PMC10177225 DOI: 10.3390/ani13091533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/27/2023] [Accepted: 04/05/2023] [Indexed: 05/15/2023] Open
Abstract
Pterygoplichthys pardalis is an armored catfish native to South America and an important resource for the ornamental fish industry. Recently, several exotic populations have been introduced into rivers on five continents. Despite its commercial and environmental importance, P. pardalis is poorly studied from a genetic perspective. In this study, we analyzed the karyotype of P. pardalis from the Amazon River and molecular variations in the mitochondrial gene Cytochrome oxidase I (COI) between native and exotic populations. The karyotype presented diploid number 2n = 52 and NF = 100 without cytogenetic variation between males and females. Nucleolus organizer regions (Ag-NOR) in the distal region of the long arm of pair 12 coincided with the 18S hybridization signal, whereas 5S was syntenic to this chromosome but localized in the short arm. The constitutive heterochromatin was restricted in the distal regions of pairs 4, 12, 25, and 26. Telomeric probes showed only distal hybridization signals. The karyotype of P. pardalis diverged from that of its congeners, and COI molecular variation revealed four haplotypes. The Philippine population revealed the greatest diversity with three haplotypes, while haplotype H1 was the most abundant and observed in both native and exotic populations. This new genetic data contributes to species management and provides useful information from an aquaculture perspective.
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Affiliation(s)
- Alcimara Dos Santos Guimarães
- Graduate Program Natural Resources of Amazonia-PPGRNA, Federal University of Western Pará-UFOPA, Tapajós Campus, Vera Paz Street, Santarém 68040-255, PA, Brazil
- Graduate Program Society, Nature and Development-PPGSND, Federal University of Western Pará-UFOPA, Tapajós Campus, Vera Paz Street, Santarém 68040-255, PA, Brazil
| | - Luan Aércio Melo Maciel
- Graduate Program Society, Nature and Development-PPGSND, Federal University of Western Pará-UFOPA, Tapajós Campus, Vera Paz Street, Santarém 68040-255, PA, Brazil
| | - Mendelshon Fujiie Belém de Souza
- Genetics and Biodiversity Laboratory-LGBio, Educational Sciences Institute-ICED, Federal University of Western Pará-UFOPA, Tapajós Campus, Vera Paz Street, Santarém 68040-255, PA, Brazil
| | - Luís Reginaldo Ribeiro Rodrigues
- Graduate Program Natural Resources of Amazonia-PPGRNA, Federal University of Western Pará-UFOPA, Tapajós Campus, Vera Paz Street, Santarém 68040-255, PA, Brazil
- Genetics and Biodiversity Laboratory-LGBio, Educational Sciences Institute-ICED, Federal University of Western Pará-UFOPA, Tapajós Campus, Vera Paz Street, Santarém 68040-255, PA, Brazil
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de Moraes RLR, Sassi FDMC, Marinho MMF, Ráb P, Porto JIR, Feldberg E, Cioffi MDB. Small Body, Large Chromosomes: Centric Fusions Shaped the Karyotype of the Amazonian Miniature Fish Nannostomus anduzei (Characiformes, Lebiasinidae). Genes (Basel) 2023; 14:192. [PMID: 36672933 PMCID: PMC9858914 DOI: 10.3390/genes14010192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/04/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
Miniature refers to species with extraordinarily small adult body size when adult and can be found within all major metazoan groups. It is considered that miniature species have experienced severe alteration of numerous morphological traits during evolution. For a variety of reasons, including severe labor concerns during collecting, chromosomal acquisition, and taxonomic issues, miniature fishes are neglected and understudied. Since some available studies indicate possible relationship between diploid chromosome number (2n) and body size in fishes, we aimed to study one of the smallest Neotropical fish Nannostomus anduzei (Teleostei, Characiformes, Lebiasinidae), using both conventional (Giemsa staining, C-banding) and molecular cytogenetic methods (FISH mapping of rDNAs, microsatellites, and telomeric sequences). Our research revealed that N. anduzei possesses one of the lowest diploid chromosome numbers (2n = 22) among teleost fishes, and its karyotype is entirely composed of large metacentric chromosomes. All chromosomes, except for pair number 11, showed an 18S rDNA signal in the pericentromeric region. 5S rDNA signals were detected in the pericentromeric regions of chromosome pair number 1 and 6, displaying synteny to 18S rDNA signals. Interstitial telomeric sites (ITS) were identified in the centromeric region of pairs 6 and 8, indicating that centric fusions played a significant role in karyotype evolution of studied species. Our study provides further evidence supporting the trend of diploid chromosome number reduction along with miniaturization of adult body size in fishes.
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Affiliation(s)
- Renata Luiza Rosa de Moraes
- Departamento de Genética e Evolução, Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luiz Km. 235, C.P. 676, São Carlos 13565-905, SP, Brazil
| | - Francisco de Menezes Cavalcante Sassi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luiz Km. 235, C.P. 676, São Carlos 13565-905, SP, Brazil
| | - Manoela Maria Ferreira Marinho
- Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, Cidade Universitária, Castelo Branco, João Pessoa 58051-900, PB, Brazil
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277 21 Liběchov, Czech Republic
| | - Jorge Ivan Rebelo Porto
- Laboratório de Genética Animal, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, Petrópolis, Manaus 69067-375, AM, Brazil
| | - Eliana Feldberg
- Laboratório de Genética Animal, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, Petrópolis, Manaus 69067-375, AM, Brazil
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luiz Km. 235, C.P. 676, São Carlos 13565-905, SP, Brazil
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Hall AN, Morton E, Queitsch C. First discovered, long out of sight, finally visible: ribosomal DNA. Trends Genet 2022; 38:587-597. [PMID: 35272860 PMCID: PMC10132741 DOI: 10.1016/j.tig.2022.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 10/18/2022]
Abstract
With the advent of long-read sequencing, previously unresolvable genomic elements are being revisited in an effort to generate fully complete reference genomes. One such element is ribosomal DNA (rDNA), the highly conserved genomic region that encodes rRNAs. Genomic structure and content of the rDNA are variable in both prokarya and eukarya, posing interesting questions about the biology of rDNA. Here, we consider the types of variation observed in rDNA - including locus structure and number, copy number, and sequence variation - and their known phenotypic consequences. With recent advances in long-read sequencing technology, incorporating the full rDNA sequence into reference genomes is within reach. This knowledge will have important implications for understanding rDNA biology within the context of cell physiology and whole-organism phenotypes.
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Affiliation(s)
- Ashley N Hall
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Elizabeth Morton
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
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Integrating Cytogenetics and Population Genomics: Allopatry and Neo-Sex Chromosomes May Have Shaped the Genetic Divergence in the Erythrinus erythrinus Species Complex (Teleostei, Characiformes). BIOLOGY 2022; 11:biology11020315. [PMID: 35205181 PMCID: PMC8869172 DOI: 10.3390/biology11020315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/13/2022] [Accepted: 02/15/2022] [Indexed: 11/18/2022]
Abstract
Simple Summary Fish present astonishing diversity, comprising more species than the combined total of all other vertebrates. Here, we integrated cytogenetic and genomic data to investigate how the evolution of multiple sex chromosomes together with allopatry is linked to genetic diversity and speciation in the fish species Erythrinus erythrinus. We hypothesized that the presence of multiple sex chromosomes has contributed to the genetic differentiation of populations, which could have potentially accelerated speciation. Abstract Diversity found in Neotropical freshwater fish is remarkable. It can even hinder a proper delimitation of many species, with the wolf fish Erythrinus erythrinus (Teleostei, Characiformes) being a notable example. This nominal species shows remarkable intra-specific variation, with extensive karyotype diversity found among populations in terms of different diploid chromosome numbers (2n), karyotype compositions and sex chromosome systems. Here, we analyzed three distinct populations (one of them cytogenetically investigated for the first time) that differed in terms of their chromosomal features (termed karyomorphs) and by the presence or absence of heteromorphic sex chromosomes. We combined cytogenetics with genomic approaches to investigate how the evolution of multiple sex chromosomes together with allopatry is linked to genetic diversity and speciation. The results indicated the presence of high genetic differentiation among populations both from cytogenetic and genomic aspects, with long-distance allopatry potentially being the main agent of genetic divergence. One population showed a neo-X1X2Y sexual chromosome system and we hypothesize that this system is associated with enhanced inter-population genetic differentiation which could have potentially accelerated speciation compared to the effect of allopatry alone.
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Sex Chromosomes and Internal Telomeric Sequences in Dormitator latifrons (Richardson 1844) (Eleotridae: Eleotrinae): An Insight into their Origin in the Genus. Genes (Basel) 2020; 11:genes11060659. [PMID: 32560434 PMCID: PMC7349016 DOI: 10.3390/genes11060659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 12/16/2022] Open
Abstract
The freshwater fish species Dormitator latifrons, commonly named the Pacific fat sleeper, is an important food resource in CentralSouth America, yet almost no genetic information on it is available. A cytogenetic analysis of this species was undertaken by standard and molecular techniques (chromosomal mapping of 18S rDNA, 5S rDNA, and telomeric repeats), aiming to describe the karyotype features, verify the presence of sex chromosomes described in congeneric species, and make inferences on chromosome evolution in the genus. The karyotype (2n = 46) is mainly composed of metacentric and submetacentic chromosomes, with nucleolar organizer regions (NORs) localized on the short arms of submetacentric pair 10. The presence of XX/XY sex chromosomes was observed, with the X chromosome carrying the 5S rDNA sequences. These heterochromosomes likely appeared before 1 million years ago, since they are shared with another derived Dormitator species (Dormitator maculatus) distributed in the Western Atlantic. Telomeric repeats hybridize to the terminal portions of almost all chromosomes; additional interstitial sites are present in the centromeric region, suggesting pericentromeric inversions as the main rearrangement mechanisms that has driven karyotypic evolution in the genus. The data provided here contribute to improving the cytogenetics knowledge of D. latifrons, offering basic information that could be useful in aquaculture farming of this neotropical fish.
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Sember A, Pelikánová Š, de Bello Cioffi M, Šlechtová V, Hatanaka T, Do Doan H, Knytl M, Ráb P. Taxonomic Diversity Not Associated with Gross Karyotype Differentiation: The Case of Bighead Carps, Genus Hypophthalmichthys (Teleostei, Cypriniformes, Xenocyprididae). Genes (Basel) 2020; 11:E479. [PMID: 32354012 PMCID: PMC7291238 DOI: 10.3390/genes11050479] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/31/2020] [Accepted: 04/24/2020] [Indexed: 11/30/2022] Open
Abstract
The bighead carps of the genus Hypophthalmichthys (H. molitrix and H. nobilis) are important aquaculture species. They were subjected to extensive multidisciplinary research, but with cytogenetics confined to conventional protocols only. Here, we employed Giemsa-/C-/CMA3- stainings and chromosomal mapping of multigene families and telomeric repeats. Both species shared (i) a diploid chromosome number 2n = 48 and the karyotype structure, (ii) low amount of constitutive heterochromatin, (iii) the absence of interstitial telomeric sites (ITSs), (iv) a single pair of 5S rDNA loci adjacent to one major rDNA cluster, and (v) a single pair of co-localized U1/U2 snDNA tandem repeats. Both species, on the other hand, differed in (i) the presence/absence of remarkable interstitial block of constitutive heterochromatin on the largest acrocentric pair 11 and (ii) the number of major (CMA3-positive) rDNA sites. Additionally, we applied here, for the first time, the conventional cytogenetics in H. harmandi, a species considered extinct in the wild and/or extensively cross-hybridized with H. molitrix. Its 2n and karyotype description match those found in the previous two species, while silver staining showed differences in distribution of major rDNA. The bighead carps thus represent another case of taxonomic diversity not associated with gross karyotype differentiation, where 2n and karyotype structure cannot help in distinguishing between genomes of closely related species. On the other hand, we demonstrated that two cytogenetic characters (distribution of constitutive heterochromatin and major rDNA) may be useful for diagnosis of pure species. The universality of these markers must be further verified by analyzing other pure populations of bighead carps.
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Affiliation(s)
- Alexandr Sember
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277-21 Liběchov, Czech Republic
| | - Šárka Pelikánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277-21 Liběchov, Czech Republic
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, Rod. Washington Luiz km 235 cep, São Carlos 13565-905, Brazil
| | - Vendula Šlechtová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277-21 Liběchov, Czech Republic
| | - Terumi Hatanaka
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, Rod. Washington Luiz km 235 cep, São Carlos 13565-905, Brazil
| | - Hiep Do Doan
- Research Institute of Aquaculture No. 1, Dinh Bang, Tu Son, Bac Ninh 16000, Vietnam
| | - Martin Knytl
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, 2-128-43 Prague, Czech Republic
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277-21 Liběchov, Czech Republic
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da Silva FA, Corrêa Guimarães EM, Carvalho ND, Ferreira AM, Schneider CH, Carvalho-Zilse GA, Feldberg E, Gross MC. Transposable DNA Elements in Amazonian Fish: From Genome Enlargement to Genetic Adaptation to Stressful Environments. Cytogenet Genome Res 2020; 160:148-155. [DOI: 10.1159/000507104] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 03/09/2020] [Indexed: 11/19/2022] Open
Abstract
Transposable elements have driven genome evolution and plasticity in many ways across a range of organisms. Different types of biotic and abiotic stresses can stimulate the expression or transposition of these mobile elements. Here, we cytogenetically analyzed natural fish populations of the same species living under different environmental conditions to test the influence and organization of transposable elements in their genome. Differential behavior was observed for the markers Rex 1, Rex 3, and Rex 6 in the chromosomes of individuals of the same species but coming from different environments (polluted and unpolluted). An increase in the number of Rex transposable elements in the chromosomes and their influence on the genome of populations living in a polluted environment indicates that they must be under constant adaptive evolution.
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Pinheiro Figliuolo VS, Goll L, Ferreira Viana P, Feldberg E, Gross MC. First Record on Sex Chromosomes in a Species of the Family Cynodontidae: Cynodon gibbus (Agassiz, 1829). Cytogenet Genome Res 2020; 160:29-37. [PMID: 32092757 DOI: 10.1159/000505889] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2019] [Indexed: 01/09/2023] Open
Abstract
The fish family Cynodontidae belongs to the superfamily Curimatoidea, together with the Hemiodontidae, Serrasalmidae, Parodontidae, Prochilodontidae, Chilodontidae, Curimatidae, and Anostomidae. The majority of the species of this superfamily that have been analyzed to date have a diploid chromosome number of 2n = 54. Differentiated sex chromosomes (with female heterogamety) have been observed only in the Prochilodontidae, Parodontidae, and Anostomidae. The present study provides the first description of differentiated sex chromosomes in the cynodontid species Cynodon gibbus, which has a ZZ/ZW system, and shows that repetitive DNA has played a fundamental role in the differentiation of these sex chromosomes.
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Sember A, de Oliveira EA, Ráb P, Bertollo LAC, de Freitas NL, Viana PF, Yano CF, Hatanaka T, Marinho MMF, de Moraes RLR, Feldberg E, Cioffi MDB. Centric Fusions behind the Karyotype Evolution of Neotropical Nannostomus Pencilfishes (Characiforme, Lebiasinidae): First Insights from a Molecular Cytogenetic Perspective. Genes (Basel) 2020; 11:genes11010091. [PMID: 31941136 PMCID: PMC7017317 DOI: 10.3390/genes11010091] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 02/07/2023] Open
Abstract
Lebiasinidae is a Neotropical freshwater family widely distributed throughout South and Central America. Due to their often very small body size, Lebiasinidae species are cytogenetically challenging and hence largely underexplored. However, the available but limited karyotype data already suggested a high interspecific variability in the diploid chromosome number (2n), which is pronounced in the speciose genus Nannostomus, a popular taxon in ornamental fish trade due to its remarkable body coloration. Aiming to more deeply examine the karyotype diversification in Nannostomus, we combined conventional cytogenetics (Giemsa-staining and C-banding) with the chromosomal mapping of tandemly repeated 5S and 18S rDNA clusters and with interspecific comparative genomic hybridization (CGH) to investigate genomes of four representative Nannostomus species: N. beckfordi, N. eques, N. marginatus, and N. unifasciatus. Our data showed a remarkable variability in 2n, ranging from 2n = 22 in N. unifasciatus (karyotype composed exclusively of metacentrics/submetacentrics) to 2n = 44 in N. beckfordi (karyotype composed entirely of acrocentrics). On the other hand, patterns of 18S and 5S rDNA distribution in the analyzed karyotypes remained rather conservative, with only two 18S and two to four 5S rDNA sites. In view of the mostly unchanged number of chromosome arms (FN = 44) in all but one species (N. eques; FN = 36), and with respect to the current phylogenetic hypothesis, we propose Robertsonian translocations to be a significant contributor to the karyotype differentiation in (at least herein studied) Nannostomus species. Interspecific comparative genome hybridization (CGH) using whole genomic DNAs mapped against the chromosome background of N. beckfordi found a moderate divergence in the repetitive DNA content among the species’ genomes. Collectively, our data suggest that the karyotype differentiation in Nannostomus has been largely driven by major structural rearrangements, accompanied by only low to moderate dynamics of repetitive DNA at the sub-chromosomal level. Possible mechanisms and factors behind the elevated tolerance to such a rate of karyotype change in Nannostomus are discussed.
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Affiliation(s)
- Alexandr Sember
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277 21 Liběchov, Czech Republic; (A.S.); (P.R.)
| | - Ezequiel Aguiar de Oliveira
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905, Brazil; (E.A.d.O.); (L.A.C.B.); (N.L.d.F.); (C.F.Y.); (T.H.); (R.L.R.d.M.)
- Secretaria de Estado de Educação de Mato Grosso–SEDUC-MT, Cuiabá 78049-909, Brazil
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277 21 Liběchov, Czech Republic; (A.S.); (P.R.)
| | - Luiz Antonio Carlos Bertollo
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905, Brazil; (E.A.d.O.); (L.A.C.B.); (N.L.d.F.); (C.F.Y.); (T.H.); (R.L.R.d.M.)
| | - Natália Lourenço de Freitas
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905, Brazil; (E.A.d.O.); (L.A.C.B.); (N.L.d.F.); (C.F.Y.); (T.H.); (R.L.R.d.M.)
| | - Patrik Ferreira Viana
- Instituto Nacional de Pesquisas da Amazônia, Coordenação de Biodiversidade, Av. André Araújo 2936, Petrópolis, Manaus 69067-375, Brazil; (P.F.V.); (E.F.)
| | - Cassia Fernanda Yano
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905, Brazil; (E.A.d.O.); (L.A.C.B.); (N.L.d.F.); (C.F.Y.); (T.H.); (R.L.R.d.M.)
| | - Terumi Hatanaka
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905, Brazil; (E.A.d.O.); (L.A.C.B.); (N.L.d.F.); (C.F.Y.); (T.H.); (R.L.R.d.M.)
| | - Manoela Maria Ferreira Marinho
- Universidade Federal da Paraíba (UFPB), Departamento de Sistemática e Ecologia (DSE), Laboratório de Sistemática e Morfologia de Peixes, João Pessoa 58051-090, Brazil;
| | - Renata Luiza Rosa de Moraes
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905, Brazil; (E.A.d.O.); (L.A.C.B.); (N.L.d.F.); (C.F.Y.); (T.H.); (R.L.R.d.M.)
| | - Eliana Feldberg
- Instituto Nacional de Pesquisas da Amazônia, Coordenação de Biodiversidade, Av. André Araújo 2936, Petrópolis, Manaus 69067-375, Brazil; (P.F.V.); (E.F.)
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905, Brazil; (E.A.d.O.); (L.A.C.B.); (N.L.d.F.); (C.F.Y.); (T.H.); (R.L.R.d.M.)
- Correspondence: ; Tel.: +55-16-3351-8431; Fax: +55-16-3351-8377
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Abstract
Individuals within a species can exhibit vast variation in copy number of repetitive DNA elements. This variation may contribute to complex traits such as lifespan and disease, yet it is only infrequently considered in genotype-phenotype associations. Although the possible importance of copy number variation is widely recognized, accurate copy number quantification remains challenging. Here, we assess the technical reproducibility of several major methods for copy number estimation as they apply to the large repetitive ribosomal DNA array (rDNA). rDNA encodes the ribosomal RNAs and exists as a tandem gene array in all eukaryotes. Repeat units of rDNA are kilobases in size, often with several hundred units comprising the array, making rDNA particularly intractable to common quantification techniques. We evaluate pulsed-field gel electrophoresis, droplet digital PCR, and Nextera-based whole genome sequencing as approaches to copy number estimation, comparing techniques across model organisms and spanning wide ranges of copy numbers. Nextera-based whole genome sequencing, though commonly used in recent literature, produced high error. We explore possible causes for this error and provide recommendations for best practices in rDNA copy number estimation. We present a resource of high-confidence rDNA copy number estimates for a set of S. cerevisiae and C. elegans strains for future use. We furthermore explore the possibility for FISH-based copy number estimation, an alternative that could potentially characterize copy number on a cellular level.
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Toma GA, de Moraes RLR, Sassi FDMC, Bertollo LAC, de Oliveira EA, Rab P, Sember A, Liehr T, Hatanaka T, Viana PF, Marinho MMF, Feldberg E, Cioffi MDB. Cytogenetics of the small-sized fish, Copeina guttata (Characiformes, Lebiasinidae): Novel insights into the karyotype differentiation of the family. PLoS One 2019; 14:e0226746. [PMID: 31856256 PMCID: PMC6922430 DOI: 10.1371/journal.pone.0226746] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/04/2019] [Indexed: 11/19/2022] Open
Abstract
Lebiasinidae is a small fish family composed by miniature to small-sized fishes with few cytogenetic data (most of them limited to descriptions of diploid chromosome numbers), thus preventing any evolutionary comparative studies at the chromosomal level. In the present study, we are providing, the first cytogenetic data for the red spotted tetra, Copeina guttata, including the standard karyotype, C-banding, repetitive DNA mapping by fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH), providing chromosomal patterns and novel insights into the karyotype differentiation of the family. Males and females share diploid chromosome number 2n = 42 and karyotype composed of 2 metacentric (m), 4 submetacentric (sm) and 36 subtelocentric to acrocentric (st-a) chromosomes. Blocks of constitutive heterochromatin were observed in the centromeric and interstitial regions of several chromosomes, in addition to a remarkably large distal block, heteromorphic in size, which fully corresponded with the 18S rDNA sites in the fourth chromosomal pair. This overlap was confirmed by 5S/18S rDNA dual-color FISH. On the other hand, 5S rDNA clusters were situated in the long and short arms of the 2nd and 15th pairs, respectively. No sex-linked karyotype differences were revealed by male/female CGH experiments. The genomic probes from other two lebiasinid species, Lebiasina melanoguttata and Pyrrhulina brevis, showed positive hybridization signals only in the NOR region in the genome of C. guttata. We demonstrated that karyotype diversification in lebiasinids was accompanied by a series of structural and numeric chromosome rearrangements of different types, including particularly fusions and fissions.
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Affiliation(s)
- Gustavo Akira Toma
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Renata Luiza Rosa de Moraes
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | | | - Luiz Antonio Carlos Bertollo
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Ezequiel Aguiar de Oliveira
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
- Secretaria de Estado de Educação de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Petr Rab
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Alexandr Sember
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Thomas Liehr
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
| | - Terumi Hatanaka
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | | | | | - Eliana Feldberg
- Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil
| | - Marcelo de Bello Cioffi
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
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