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Girardini KN, Olthof AM, Kanadia RN. Introns: the "dark matter" of the eukaryotic genome. Front Genet 2023; 14:1150212. [PMID: 37260773 PMCID: PMC10228655 DOI: 10.3389/fgene.2023.1150212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/02/2023] Open
Abstract
The emergence of introns was a significant evolutionary leap that is a major distinguishing feature between prokaryotic and eukaryotic genomes. While historically introns were regarded merely as the sequences that are removed to produce spliced transcripts encoding functional products, increasingly data suggests that introns play important roles in the regulation of gene expression. Here, we use an intron-centric lens to review the role of introns in eukaryotic gene expression. First, we focus on intron architecture and how it may influence mechanisms of splicing. Second, we focus on the implications of spliceosomal snRNAs and their variants on intron splicing. Finally, we discuss how the presence of introns and the need to splice them influences transcription regulation. Despite the abundance of introns in the eukaryotic genome and their emerging role regulating gene expression, a lot remains unexplored. Therefore, here we refer to introns as the "dark matter" of the eukaryotic genome and discuss some of the outstanding questions in the field.
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Affiliation(s)
- Kaitlin N. Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
| | - Anouk M. Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Rahul N. Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, United States
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2
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Noronha RCR, Almeida BRR, Chagas MCS, Tavares FS, Cardoso AL, Bastos CEMC, Silva NKN, Klautau AGCM, Luna FO, Attademo FLN, Lima DS, Sabioni LA, Sampaio MIC, Oliveira JM, do Nascimento LAS, Martins C, Vicari MR, Nagamachi CY, Pieczarka JC. Karyotypes of Manatees: New Insights into Hybrid Formation ( Trichechus inunguis × Trichechus m. manatus) in the Amazon Estuary. Genes (Basel) 2022; 13:1263. [PMID: 35886048 PMCID: PMC9323068 DOI: 10.3390/genes13071263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/11/2022] [Accepted: 07/14/2022] [Indexed: 02/01/2023] Open
Abstract
Great efforts have been made to preserve manatees. Recently, a hybrid zone was described between Trichechus inunguis (TIN) and the Trichechus manatus manatus (TMM) in the Amazon estuary. Cytogenetic data on these sirenians are limited, despite being fundamental to understanding the hybridization/introgression dynamics and genomic organization in Trichechus. We analyzed the karyotype of TMM, TIN, and two hybrid specimens ("Poque" and "Vitor") by classical and molecular cytogenetics. G-band analysis revealed that TMM (2n = 48) and TIN (2n = 56) diverge by at least six Robertsonian translocations and a pericentric inversion. Hybrids had 2n = 50, however, with Autosomal Fundamental Number (FNA) = 88 in "Poque" and FNA = 74 in "Vitor", and chromosomal distinct pairs in heterozygous; additionally, "Vitor" exhibited heteromorphisms and chromosomes whose pairs could not be determined. The U2 snDNA and Histone H3 multi genes are distributed in small clusters along TIN and TMM chromosomes and have transposable Keno and Helitron elements (TEs) in their sequences. The different karyotypes observed among manatee hybrids may indicate that they represent different generations formed by crossing between fertile hybrids and TIN. On the other hand, it is also possible that all hybrids recorded represent F1 and the observed karyotype differences must result from mechanisms of elimination.
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Affiliation(s)
- Renata C. R. Noronha
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (B.R.R.A.); (M.C.S.C.); (F.S.T.); (C.E.M.C.B.); (C.Y.N.); (J.C.P.)
| | - Bruno R. R. Almeida
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (B.R.R.A.); (M.C.S.C.); (F.S.T.); (C.E.M.C.B.); (C.Y.N.); (J.C.P.)
- Campus Itaituba, Instituto Federal de Educação, Ciência e Tecnologia do Pará, Itaituba 68183-300, PA, Brazil
| | - Monique C. S. Chagas
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (B.R.R.A.); (M.C.S.C.); (F.S.T.); (C.E.M.C.B.); (C.Y.N.); (J.C.P.)
| | - Flávia S. Tavares
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (B.R.R.A.); (M.C.S.C.); (F.S.T.); (C.E.M.C.B.); (C.Y.N.); (J.C.P.)
| | - Adauto L. Cardoso
- Laboratório Genômica Integrativa, Departamento de Biologia Estrutural e Funcional, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Botucatu 18618-970, SP, Brazil; (A.L.C.); (C.M.)
| | - Carlos E. M. C. Bastos
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (B.R.R.A.); (M.C.S.C.); (F.S.T.); (C.E.M.C.B.); (C.Y.N.); (J.C.P.)
| | - Natalia K. N. Silva
- Campus Tucuruí, Universidade do Estado do Pará, Tucuruí 68455-210, PA, Brazil;
| | - Alex G. C. M. Klautau
- Centro Nacional de Pesquisa e Conservação da Biodiversidade Marinha do Norte, Instituto Chico Mendes de Conservação da Biodiversidade, Belém 66635-110, PA, Brazil;
| | - Fábia O. Luna
- Centro Nacional de Pesquisa e Conservação de Mamíferos Aquáticos, Instituto Chico Mendes de Conservação de Biodiversidade, Santos 11050-031, SP, Brazil; (F.O.L.); (F.L.N.A.)
| | - Fernanda L. N. Attademo
- Centro Nacional de Pesquisa e Conservação de Mamíferos Aquáticos, Instituto Chico Mendes de Conservação de Biodiversidade, Santos 11050-031, SP, Brazil; (F.O.L.); (F.L.N.A.)
- Departamento de Zoologia, Programa de Pós-Graduação em Biologia Animal/PPBA, Laboratório de Ecologia Comportamento e Conservação/LECC, Universidade Federal de Pernambuco/UFPE, Recife 50670-901, PE, Brazil
| | - Danielle S. Lima
- Grupo de Pesquisa em Mamíferos Aquáticos Amazônicos, Instituto de Desenvolvimento Sustentável Mamirauá, Estrada do Bexiga, Tefé 69553-225, AM, Brazil; (D.S.L.); (L.A.S.)
- Rede de Pesquisa e Conservação de Sirênios no Estuário Amazônico, Macapá 68903-197, AP, Brazil
| | - Luiz A. Sabioni
- Grupo de Pesquisa em Mamíferos Aquáticos Amazônicos, Instituto de Desenvolvimento Sustentável Mamirauá, Estrada do Bexiga, Tefé 69553-225, AM, Brazil; (D.S.L.); (L.A.S.)
- Rede de Pesquisa e Conservação de Sirênios no Estuário Amazônico, Macapá 68903-197, AP, Brazil
- Campus Porto Grande, Instituto Federal de Educação Ciência e Tecnologia do Amapá, Rodovia BR 210, Km 103, s/n, Zona Rural, Porto Grande 68997-000, AP, Brazil
| | - Maria I. C. Sampaio
- Instituto de Estudos Costeiros, Campus Bragança, Universidade Federal do Pará, Bragança 68600-000, PA, Brazil;
| | - Jairo Moura Oliveira
- Zoological Park of Santarém, ZOOUNAMA, Universidade da Amazônia, Santarém 68030-150, PA, Brazil;
| | | | - Cesar Martins
- Laboratório Genômica Integrativa, Departamento de Biologia Estrutural e Funcional, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Botucatu 18618-970, SP, Brazil; (A.L.C.); (C.M.)
| | - Marcelo R. Vicari
- Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Ponta Grossa 84030-900, PR, Brazil;
| | - Cleusa Y. Nagamachi
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (B.R.R.A.); (M.C.S.C.); (F.S.T.); (C.E.M.C.B.); (C.Y.N.); (J.C.P.)
| | - Julio C. Pieczarka
- Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém 66075-110, PA, Brazil; (B.R.R.A.); (M.C.S.C.); (F.S.T.); (C.E.M.C.B.); (C.Y.N.); (J.C.P.)
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Azambuja M, Orane Schemberger M, Nogaroto V, Moreira-Filho O, Martins C, Ricardo Vicari M. Major and minor U small nuclear RNAs genes characterization in a neotropical fish genome: Chromosomal remodeling and repeat units dispersion in Parodontidae. Gene 2022; 826:146459. [PMID: 35358649 DOI: 10.1016/j.gene.2022.146459] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/15/2022] [Accepted: 03/25/2022] [Indexed: 11/29/2022]
Abstract
In association with many proteins, small nuclear RNAs (snRNAs) organize the spliceosomes that play a significant role in processing precursor mRNAs during gene expression. According to snRNAs genic arrangements, two kinds of spliceosomes (major and minor) can be organized into eukaryotic cells. Although in situ localization of U1 and U2 snDNAs have been performed in fish karyotypes, studies with genomic characterization and functionality of U snRNAs integrated into chromosomal changes on Teleostei are still scarce. This study aimed to achieve a genomic characterization of the U snRNAs genes in Apareiodon sp. (2n = 54, ZZ/ZW), apply these data to recognize functional/defective copies, and map chromosomal changes involving snDNAs in Parodontidae species karyotype diversification. Nine snRNA multigene families (U1, U2, U4, U5, U6, U11, U12, U4atac and U6atac) arranged in putatively functional copies in the genome were analyzed. Proximal Sequence Elements (PSE) and TATA-box promoters occurrence, besides an entire transcribed region and conserved secondary structures, qualify them for spliceosome activity. In addition, several defective copies or pseudogenes were identified for the snRNAs that make up the major spliceosome. In situ localization of snDNAs in five species of Parodontidae demonstrated that U1, U2, and U4 snDNAs were involved in chromosomal location changes or units dispersion. The U snRNAs defective/pseudogenes units dispersion could be favored by the probable occurrence of active retrotransposition enzymes in the Apareiodon genome. The U2 and U4 snDNAs sites were involved in independent events in the differentiation of sex chromosomes among Parodontidae lineages. The study characterized U snRNA genes that compose major and minor spliceosomes in the Apareiodon sp. genome and proposes that their defective copies trigger chromosome differentiation and diversification events in Parodontidae.
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Affiliation(s)
- Matheus Azambuja
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Centro Politécnico, Avenida Coronel Francisco H. dos Santos, 100, 81531-990 Curitiba, Paraná, Brazil.
| | - Michelle Orane Schemberger
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Centro Politécnico, Avenida Coronel Francisco H. dos Santos, 100, 81531-990 Curitiba, Paraná, Brazil.
| | - Viviane Nogaroto
- Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
| | - Orlando Moreira-Filho
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, Rodovia Washington Luís, Km 235, 13565-905 São Carlos, São Paulo, Brazil.
| | - Cesar Martins
- Departamento de Morfologia, Instituto de Biociências de Botucatu, Universidade Estadual Paulista, Distrito de Rubião Júnior, s/n, 18618-689 Botucatu, São Paulo, Brazil.
| | - Marcelo Ricardo Vicari
- Programa de Pós-Graduação em Genética, Universidade Federal do Paraná, Centro Politécnico, Avenida Coronel Francisco H. dos Santos, 100, 81531-990 Curitiba, Paraná, Brazil; Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
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Santander MD, Cabral-de-Mello DC, Taffarel A, Martí E, Martí DA, Palacios-Gimenez OM, Castillo ERD. New insights into the six decades of Mesa’s hypothesis of chromosomal evolution in Ommexechinae grasshoppers (Orthoptera: Acridoidea). Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlaa188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
In Acridoidea grasshoppers, chromosomal rearrangements are frequently found as deviations from the standard acrocentric karyotype (2n = 23♂/24♀, FN = 23♂/24♀) in either phylogenetically unrelated species or shared by closely related ones, i.e. genus. In the South American subfamily Ommexechinae, most of the species show a unique karyotype (2n = 23♂/24♀, FN = 25♂/26♀) owing to the occurrence of a large autosomal pair (L1) with submetacentric morphology. In the early 1960s, Alejo Mesa proposed the hypothesis of an ancestral pericentric inversion to explain this karyotype variation. Furthermore, in Ommexechinae, extra chromosomal rearrangements (e.g. centric fusions) are recorded between the ancestral X chromosome and autosomes that originated the so-called neo-sex chromosomes. However, the evolutionary significance of the pericentric inversions and centric fusions in Ommexechinae remains poorly explored. Aiming for a better understanding of chromosomal evolution in Ommexechinae, we performed a detailed cytogenetic analysis in five species. Our findings support the hypothesis about the occurrence of an early pericentric inversion in the ancestor of Ommexechinae. Moreover, our results show a complex karyotype diversification pattern due to several chromosome rearrangements, variations in heterochromatin and repetitive DNA dynamics. Finally, the chromosomal mapping of U2 snDNA in L1 provided new insights about the morphological evolution of this autosomal pair and revealed unnoticed chromosome reorganizations.
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Affiliation(s)
- Mylena D Santander
- Laboratorio de Genética Evolutiva Dr. Claudio J. Bidau. Instituto de Biología Subtropical (IBS) CONICET-UNaM. FCEQyN. Posadas, Misiones, Argentina
- Departamento de Genética e Biologia Evolutiva. Instituto de Biociências, Universidade de São Paulo (USP). São Paulo, São Paulo, Brazil
| | - Diogo C Cabral-de-Mello
- Departamento de Biologia Geral e Aplicada, Universidade Estadual Paulista (UNESP), Instituto de Biociências/IB. Rio Claro, São Paulo, Brazil
| | - Alberto Taffarel
- Laboratorio de Genética Evolutiva Dr. Claudio J. Bidau. Instituto de Biología Subtropical (IBS) CONICET-UNaM. FCEQyN. Posadas, Misiones, Argentina
| | - Emiliano Martí
- Departamento de Biologia Geral e Aplicada, Universidade Estadual Paulista (UNESP), Instituto de Biociências/IB. Rio Claro, São Paulo, Brazil
| | - Dardo A Martí
- Laboratorio de Genética Evolutiva Dr. Claudio J. Bidau. Instituto de Biología Subtropical (IBS) CONICET-UNaM. FCEQyN. Posadas, Misiones, Argentina
| | - Octavio M Palacios-Gimenez
- Department of Organismal Biology – Systematic Biology Program, Evolutionary Biology Centre, Uppsala University
| | - Elio Rodrigo D Castillo
- Laboratorio de Genética Evolutiva Dr. Claudio J. Bidau. Instituto de Biología Subtropical (IBS) CONICET-UNaM. FCEQyN. Posadas, Misiones, Argentina
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Martí E, Milani D, Bardella VB, Albuquerque L, Song H, Palacios-Gimenez OM, Cabral-de-Mello DC. Cytogenomic analysis unveils mixed molecular evolution and recurrent chromosomal rearrangements shaping the multigene families on Schistocerca grasshopper genomes. Evolution 2021; 75:2027-2041. [PMID: 34155627 DOI: 10.1111/evo.14287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/11/2021] [Accepted: 05/26/2021] [Indexed: 11/26/2022]
Abstract
Multigene families are essential components of eukaryotic genomes and play key roles either structurally and functionally. Their modes of evolution remain elusive even in the era of genomics, because multiple multigene family sequences coexist in genomes, particularly in large repetitive genomes. Here, we investigate how the multigene families 18S rDNA, U2 snDNA, and H3 histone evolved in 10 species of Schistocerca grasshoppers with very large and repeat-enriched genomes. Using sequenced genomes and fluorescence in situ hybridization mapping, we find substantial differences between species, including the number of chromosomal clusters, changes in sequence abundance and nucleotide composition, pseudogenization, and association with transposable elements (TEs). The intragenomic analysis of Schistocerca gregaria using long-read sequencing and genome assembly unveils conservation for H3 histone and recurrent pseudogenization for 18S rDNA and U2 snDNA, likely promoted by association with TEs and sequence truncation. Remarkably, TEs were frequently associated with truncated copies, were also among the most abundant in the genome, and revealed signatures of recent activity. Our findings suggest a combined effect of concerted and birth-and-death models driving the evolution of multigene families in Schistocerca over the last 8 million years, and the occurrence of intra- and interchromosomal rearrangements shaping their chromosomal distribution. Despite the conserved karyotype in Schistocerca, our analysis highlights the extensive reorganization of repetitive DNAs in Schistocerca, contributing to the advance of comparative genomics for this important grasshopper genus.
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Affiliation(s)
- Emiliano Martí
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Diogo Milani
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Vanessa B Bardella
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Lucas Albuquerque
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Hojun Song
- Department of Entomology, Texas A&M University, College Station, Texas, 77843
| | - Octavio M Palacios-Gimenez
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, SE-75236, Sweden.,Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Jena, DE-07743, Germany
| | - Diogo C Cabral-de-Mello
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
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Provazníková I, Hejníčková M, Visser S, Dalíková M, Carabajal Paladino LZ, Zrzavá M, Voleníková A, Marec F, Nguyen P. Large-scale comparative analysis of cytogenetic markers across Lepidoptera. Sci Rep 2021; 11:12214. [PMID: 34108567 PMCID: PMC8190105 DOI: 10.1038/s41598-021-91665-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/24/2021] [Indexed: 11/25/2022] Open
Abstract
Fluorescence in situ hybridization (FISH) allows identification of particular chromosomes and their rearrangements. Using FISH with signal enhancement via antibody amplification and enzymatically catalysed reporter deposition, we evaluated applicability of universal cytogenetic markers, namely 18S and 5S rDNA genes, U1 and U2 snRNA genes, and histone H3 genes, in the study of the karyotype evolution in moths and butterflies. Major rDNA underwent rather erratic evolution, which does not always reflect chromosomal changes. In contrast, the hybridization pattern of histone H3 genes was well conserved, reflecting the stable organisation of lepidopteran genomes. Unlike 5S rDNA and U1 and U2 snRNA genes which we failed to detect, except for 5S rDNA in a few representatives of early diverging lepidopteran lineages. To explain the negative FISH results, we used quantitative PCR and Southern hybridization to estimate the copy number and organization of the studied genes in selected species. The results suggested that their detection was hampered by long spacers between the genes and/or their scattered distribution. Our results question homology of 5S rDNA and U1 and U2 snRNA loci in comparative studies. We recommend the use of histone H3 in studies of karyotype evolution.
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Affiliation(s)
- Irena Provazníková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Martina Hejníčková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | - Sander Visser
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Martina Dalíková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | | | - Magda Zrzavá
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | - Anna Voleníková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | - František Marec
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | - Petr Nguyen
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic.
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Cabral-de-Mello DC, Marec F. Universal fluorescence in situ hybridization (FISH) protocol for mapping repetitive DNAs in insects and other arthropods. Mol Genet Genomics 2021; 296:513-526. [PMID: 33625598 DOI: 10.1007/s00438-021-01765-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 01/29/2021] [Indexed: 12/30/2022]
Abstract
Repetitive DNAs comprise large portion of eukaryote genomes. In genome projects, the assembly of repetitive DNAs is challenging due to the similarity between repeats, which generate ambiguities for alignment. Fluorescence in situ hybridization (FISH) is a powerful technique for the physical mapping of various sequences on chromosomes. This technique is thus very helpful in chromosome-based genome assemblies, providing information on the fine architecture of genomes and their evolution. However, various protocols are currently used for FISH mapping, most of which are relatively laborious and expensive, or work properly only with a specific type of probes or sequences, and there is a need for a universal and affordable FISH protocol. Here we tested a FISH protocol for mapping of different DNA repeats, such as multigene families (rDNAs, U snDNAs, histone genes), satellite DNAs, microsatellites, transposable elements, DOP-PCR products, and telomeric motif (TTAGG)n, on the chromosomes of various insects and other arthropods. Different cell types and stages obtained from diverse tissues were used. The FISH procedure proved high quality and reliable results in all experiments performed. We obtained data on the chromosomal distribution of DNA repeats in representatives of insects and other arthropods. Thus, our results allow us to conclude that the protocol is universal and requires only time adjustment for chromosome/DNA denaturation. The use of this FISH protocol will facilitate studies focused on understanding the evolution and role of repetitive DNA in arthropod genomes.
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Affiliation(s)
- Diogo Cavalcanti Cabral-de-Mello
- Departamento de Biologia Geral e Aplicada, Instituto de Biociências, UNESP- Universidade Estadual Paulista, Rio Claro, São Paulo, CEP 13506-900, Brazil.
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, České Budějovice, Czech Republic.
| | - František Marec
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, České Budějovice, Czech Republic
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Zattera ML, Gazolla CB, Soares ADA, Gazoni T, Pollet N, Recco-Pimentel SM, Bruschi DP. Evolutionary Dynamics of the Repetitive DNA in the Karyotypes of Pipa carvalhoi and Xenopus tropicalis (Anura, Pipidae). Front Genet 2020; 11:637. [PMID: 32793276 PMCID: PMC7385237 DOI: 10.3389/fgene.2020.00637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/26/2020] [Indexed: 01/01/2023] Open
Abstract
The large amphibian genomes contain numerous repetitive DNA components that have played an important role in the karyotypic diversification of this vertebrate group. Hypotheses based on the presumable primitive karyotype (2n = 20) of the anurans of the family Pipidae suggest that they have evolved principally through intrachromosomal rearrangements. Pipa is the only South American pipid, while all the other genera are found in Africa. The divergence of the South American lineages from the African ones occurred at least 136 million years ago and is thought to have had a strong biogeographic component. Here, we tested the potential of the repetitive DNA to enable a better understanding of the differentiation of the karyotype among the family Pipidae and to expand our capacity to interpret the chromosomal evolution in this frog family. Our results indicate a long history of conservation in the chromosome bearing the H3 histone locus, corroborating inferences on the chromosomal homologies between the species in pairs 6, 8, and 9. The chromosomal distribution of the microsatellite motifs also provides useful markers for comparative genomics at the chromosome level between Pipa carvalhoi and Xenopus tropicalis, contributing new insights into the evolution of the karyotypes of these species. We detected similar patterns in the distribution and abundance of the microsatellite arrangements, which reflect the shared organization in the terminal/subterminal region of the chromosomes between these two species. By contrast, the microsatellite probes detected a differential arrangement of the repetitive DNA among the chromosomes of the two species, allowing longitudinal differentiation of pairs that are identical in size and morphology, such as pairs 1, 2, 4, and 5. We also found evidence of the distinctive composition of the repetitive motifs of the centromeric region between the species analyzed in the present study, with a clear enrichment of the (CA) and (GA) microsatellite motifs in P. carvalhoi. Finally, microsatellite enrichment in the pericentromeric region of chromosome pairs 6, 8, and 9 in the P. carvalhoi karyotype, together with interstitial telomeric sequences (ITS), validate the hypothesis that pericentromeric inversions occurred during the chromosomal evolution of P. carvalhoi and reinforce the role of the repetitive DNA in the remodeling of the karyotype architecture of the Pipidae.
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Affiliation(s)
- Michelle Louise Zattera
- Programa de Pós-Graduação em Genética (PPG-GEN), Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Camilla Borges Gazolla
- Programa de Pós-Graduação em Genética (PPG-GEN), Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Amanda de Araújo Soares
- Programa de Pós-Graduação em Genética (PPG-GEN), Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Thiago Gazoni
- Universidade Estadual Paulista (Unesp), Campus Rio Claro, Rio Claro, Brazil
| | - Nicolas Pollet
- Laboratoire Evolution Genomes Comportement Ecologie, CNRS, IRD, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Daniel Pacheco Bruschi
- Programa de Pós-Graduação em Genética (PPG-GEN), Universidade Federal do Paraná (UFPR), Curitiba, Brazil
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9
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Anjos A, Paladini A, Evangelista O, Cabral‐de‐Mello DC. Insights into chromosomal evolution of Cicadomorpha using fluorochrome staining and mapping 18S rRNA and H3 histone genes. J ZOOL SYST EVOL RES 2018. [DOI: 10.1111/jzs.12254] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Allison Anjos
- Departamento de BiologiaInstituto de BiociênciasUNESP Rio Claro SP Brazil
| | - Andressa Paladini
- Departamento de Ecologia e EvoluçãoUniversidade Federal de Santa Maria Santa Maria RS Brazil
| | - Olivia Evangelista
- Australian National Insect CollectionCSIRO National Research Collections Australia Canberra Australia
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10
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Piscor D, Fernandes CA, Parise-Maltempi PP. Conserved number of U2 snDNA sites in Piabina argentea, Piabarchus stramineus and two Bryconamericus species (Characidae, Stevardiinae). NEOTROPICAL ICHTHYOLOGY 2018. [DOI: 10.1590/1982-0224-20170066] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT The chromosomal location of 5S rRNA and U2 snRNA genes of Piabina argentea, Piabarchus stramineus and two Bryconamericus species from two different Brazilian river basins were investigated, in order to contribute to the understanding of evolutionary characteristics of these repetitive DNAs in the subfamily Stevardiinae. The diploid chromosome number was 2n = 52 for Bryconamericus cf. iheringii, Bryconamericus turiuba, Piabarchus stramineus and Piabina argentea. The 5S rDNA clusters were located on one chromosome pair in P. stramineus and B. cf. iheringii, and on two pairs in B. turiuba and P. argentea. The U2 snDNA clusters were located on the one pair in all species. Two-color FISH experiments showed that the co-localization between 5S rDNA and U2 snDNA in P. stramineus can represent a marker for this species. Thus, the present study demonstrated that the number of U2 snDNA clusters observed for the four species was conserved, but particular characteristics can be found in the genome of each species.
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Affiliation(s)
- Diovani Piscor
- Universidade Estadual Paulista “Júlio de Mesquita Filho”, Brazil
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11
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Anjos A, Paladini A, Mariguela TC, Cabral-de-Mello DC. U1 snDNA chromosomal mapping in ten spittlebug species (Cercopidade, Auchenorrhyncha, Hemiptera). Genome 2018; 61:59-62. [DOI: 10.1139/gen-2017-0151] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Spittlebugs, which belong to the family Cercopidae (Auchenorrhyncha, Hemiptera), form a large group of xylem-feeding insects that are best known for causing damage to plantations and pasture grasses. The holocentric chromosomes of these insects remain poorly studied in regards to the organization of different classes of repetitive DNA. To improve chromosomal maps based on repetitive DNAs and to better understand the chromosomal organization and evolutionary dynamics of multigene families in spittlebugs, we physically mapped the U1 snRNA gene with fluorescence in situ hybridization (FISH) in 10 species of Cercopidae belonging to three different genera. All the U1 snDNA clusters were autosomal and located in interstitial position. In seven species, they were restricted to one autosome per haploid genome, while three species of the genus Mahanarva showed two clusters in two different autosomes. Although it was not possible to precisely define the ancestral location of this gene, it was possible to observe the presence of at least one cluster located in a small bivalent in all karyotypes. The karyotype stability observed in Cercopidae is also observed in respect to the distribution of U1 snDNA. Our data are discussed in light of possible mechanisms for U1 snDNA conservation and compared with the available data from other species.
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Affiliation(s)
- Allison Anjos
- Departamento de Biologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
| | - Andressa Paladini
- Departamento de Ecologia e Evolução, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Tatiane C. Mariguela
- Departamento de Biologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
| | - Diogo C. Cabral-de-Mello
- Departamento de Biologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
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12
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Jetybayev IY, Bugrov AG, Buleu OG, Bogomolov AG, Rubtsov NB. Origin and Evolution of the Neo-Sex Chromosomes in Pamphagidae Grasshoppers through Chromosome Fusion and Following Heteromorphization. Genes (Basel) 2017; 8:genes8110323. [PMID: 29137168 PMCID: PMC5704236 DOI: 10.3390/genes8110323] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 11/16/2022] Open
Abstract
In most phylogenetic lineages, the evolution of sex chromosomes is accompanied by their heteromorphization and degradation of one of them. The neo-sex chromosomes are useful model for studying early stages of these processes. Recently two lineages of the neo-sex chromosomes on different stages of heteromorphization was discovered in Pamphagidae family. The neo-sex chromosome heteromorphization was analyzed by generation of DNA probes derived from the neo-Xs and neo-Ys followed with chromosome painting in nineteen species of Pamphagidae family. The homologous regions of the neo-sex chromosomes were determined in closely related species with the painting procedure and image analysis with application of the Visualization of the Specific Signal in Silico software package. Results of these analyses and distribution of C-positive regions in the neo-sex chromosomes revealed details of the heteromorphization of the neo-sex chromosomes in species from both phylogenetic lineages of Pamphagidae grasshoppers. The hypothetical mechanism of the neo-Y degradation was suggested. It includes expansion of different repeats from the proximal neo-Y chromosome region by inversions, spreading them towards distal region. Amplification of these repeats leads to formation of C-positive regions and elimination of the C-negative regions located between them.
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Affiliation(s)
- Ilyas Yerkinovich Jetybayev
- The Federal Research Center, Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Lavrentjev Ave., 10, 630090 Novosibirsk, Russia.
- Institute of Systematics and Ecology of Animals, Russian Academy of Sciences, Siberian Branch, Frunze str. 11, 630091 Novosibirsk, Russia.
| | - Alexander Gennadievich Bugrov
- Institute of Systematics and Ecology of Animals, Russian Academy of Sciences, Siberian Branch, Frunze str. 11, 630091 Novosibirsk, Russia.
- Novosibirsk State University, Department of Natural Sciences, Pirogov str., 2, 630090 Novosibirsk, Russia.
| | - Olesya Georgievna Buleu
- Institute of Systematics and Ecology of Animals, Russian Academy of Sciences, Siberian Branch, Frunze str. 11, 630091 Novosibirsk, Russia.
- Novosibirsk State University, Department of Natural Sciences, Pirogov str., 2, 630090 Novosibirsk, Russia.
| | - Anton Gennadievich Bogomolov
- The Federal Research Center, Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Lavrentjev Ave., 10, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Department of Natural Sciences, Pirogov str., 2, 630090 Novosibirsk, Russia.
| | - Nikolay Borisovich Rubtsov
- The Federal Research Center, Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Lavrentjev Ave., 10, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Department of Natural Sciences, Pirogov str., 2, 630090 Novosibirsk, Russia.
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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] [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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14
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Anjos A, Rocha GC, Paladini A, Mariguela TC, Cabral-de-Mello DC. Karyotypes and Repetitive DNA Evolution in Six Species of the Genus Mahanarva (Auchenorrhyncha: Cercopidae). Cytogenet Genome Res 2016; 149:321-327. [PMID: 27811473 DOI: 10.1159/000450730] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2016] [Indexed: 11/19/2022] Open
Abstract
Insects of the Cercopidae family are widely distributed and comprise 59 genera and 431 species in the New World. They are xylemophagous, causing losses in agricultural and pasture grasses, and are considered as emerging pests. Chromosomally, these insects have been studied by standard techniques, revealing variable diploid numbers and primarily X0 sex chromosome systems (males). We performed chromosome studies in 6 Mahanarva (Cercopidae) species using standard and differential chromosome staining as well as mapping of repetitive DNAs. Moreover, the relationship between the repetitive DNAs was analyzed at the interspecific level. A diploid chromosome number of 2n = 19,X0 was documented, with chromosomes gradually decreasing in size. Neutral or GC-rich regions were detected which varied depending on the species. Fluorescence in situ hybridization with a (TTAGG)n telomeric motif probe revealed terminal signals, matching those of the Cot DNAs obtained from each species, that were also restricted to the terminal regions of all chromosomes. Dot blot analysis with the Cot fraction from M. quadripunctata showed that at least part of the repetitive genome is shared among the 6 species. Our data highlight the conservation of chromosomal features and organization of repetitive DNAs in the genus Mahanarva, suggesting a low differentiation for chromosomes and repetitive DNAs in most of the 6 species studied.
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Affiliation(s)
- Allison Anjos
- Departamento de Biologia, Instituto de Biociências, UNESP, Rio Claro, Brazil
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15
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Ruiz-Ruano FJ, López-León MD, Cabrero J, Camacho JPM. High-throughput analysis of the satellitome illuminates satellite DNA evolution. Sci Rep 2016; 6:28333. [PMID: 27385065 PMCID: PMC4935994 DOI: 10.1038/srep28333] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 06/02/2016] [Indexed: 12/22/2022] Open
Abstract
Satellite DNA (satDNA) is a major component yet the great unknown of eukaryote genomes and clearly underrepresented in genome sequencing projects. Here we show the high-throughput analysis of satellite DNA content in the migratory locust by means of the bioinformatic analysis of Illumina reads with the RepeatExplorer and RepeatMasker programs. This unveiled 62 satDNA families and we propose the term "satellitome" for the whole collection of different satDNA families in a genome. The finding that satDNAs were present in many contigs of the migratory locust draft genome indicates that they show many genomic locations invisible by fluorescent in situ hybridization (FISH). The cytological pattern of five satellites showing common descent (belonging to the SF3 superfamily) suggests that non-clustered satDNAs can become into clustered through local amplification at any of the many genomic loci resulting from previous dissemination of short satDNA arrays. The fact that all kinds of satDNA (micro- mini- and satellites) can show the non-clustered and clustered states suggests that all these elements are mostly similar, except for repeat length. Finally, the presence of VNTRs in bacteria, showing similar properties to non-clustered satDNAs in eukaryotes, suggests that this kind of tandem repeats show common properties in all living beings.
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Affiliation(s)
| | | | - Josefa Cabrero
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Juan Pedro M. Camacho
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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16
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Chromosomal evolutionary dynamics of four multigene families in Coreidae and Pentatomidae (Heteroptera) true bugs. Mol Genet Genomics 2016; 291:1919-25. [DOI: 10.1007/s00438-016-1229-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 06/22/2016] [Indexed: 12/31/2022]
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17
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The 5S rDNA in two Abracris grasshoppers (Ommatolampidinae: Acrididae): molecular and chromosomal organization. Mol Genet Genomics 2016; 291:1607-13. [PMID: 27106499 DOI: 10.1007/s00438-016-1204-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/30/2016] [Indexed: 10/21/2022]
Abstract
The 5S ribosomal DNA (rDNA) sequences are subject of dynamic evolution at chromosomal and molecular levels, evolving through concerted and/or birth-and-death fashion. Among grasshoppers, the chromosomal location for this sequence was established for some species, but little molecular information was obtained to infer evolutionary patterns. Here, we integrated data from chromosomal and nucleotide sequence analysis for 5S rDNA in two Abracris species aiming to identify evolutionary dynamics. For both species, two arrays were identified, a larger sequence (named type-I) that consisted of the entire 5S rDNA gene plus NTS (non-transcribed spacer) and a smaller (named type-II) with truncated 5S rDNA gene plus short NTS that was considered a pseudogene. For type-I sequences, the gene corresponding region contained the internal control region and poly-T motif and the NTS presented partial transposable elements. Between the species, nucleotide differences for type-I were noticed, while type-II was identical, suggesting pseudogenization in a common ancestor. At chromosomal point to view, the type-II was placed in one bivalent, while type-I occurred in multiple copies in distinct chromosomes. In Abracris, the evolution of 5S rDNA was apparently influenced by the chromosomal distribution of clusters (single or multiple location), resulting in a mixed mechanism integrating concerted and birth-and-death evolution depending on the unit.
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18
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Anjos A, Loreto V, Cabral-de-Mello DC. Organization of some repetitive DNAs and B chromosomes in the grasshopper Eumastusia koebelei koebelei (Rehn, 1909) (Orthoptera, Acrididae, Leptysminae). COMPARATIVE CYTOGENETICS 2016; 10:219-28. [PMID: 27551344 PMCID: PMC4977798 DOI: 10.3897/compcytogen.v10i2.7609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/03/2016] [Indexed: 05/05/2023]
Abstract
B chromosomes occur in approximately 15% of eukaryotes and are usually heterochromatic and rich in repetitive DNAs. Here we describe characteristics of a B chromosome in the grasshopper Eumastusia koebelei koebelei (Rehn, 1909) through classical cytogenetic methods and mapping of some repetitive DNAs, including multigene families, telomeric repeats and a DNA fraction enriched with repetitive DNAs obtained from DOP-PCR. Eumastusia koebelei koebelei presented 2n=23, X0 and, in one individual, two copies of the same variant of a B chromosome were noticed, which are associated during meiosis. The C-positive blocks were located in the pericentromeric regions of the standard complement and along the entire length of the B chromosomes. Some G+C-rich heterochromatic blocks were noticed, including conspicuous blocks in the B chromosomes. The mapping of 18S rDNA and U2 snDNA revealed only autosomal clusters, and the telomeric probe hybridized in terminal regions. Finally, the DOP-PCR probe obtained from an individual without a B chromosome revealed signals in the heterochromatic regions, including the entire length of the B chromosome. The possible intraspecific origin of the B chromosomes, due to the shared pool of repetitive DNAs between the A and B chromosomes and the possible consequences of their association are discussed.
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Affiliation(s)
- Allison Anjos
- Departamento de Biologia, Instituto de Biociências, UNESP, Rio Claro, São Paulo, CEP 13506-900, Brazil
| | - Vilma Loreto
- Departamento de Genética, Centro de Ciências Biológicas, UFPE, Recife, Pernambuco, 50732-970, Brazil
| | - Diogo C. Cabral-de-Mello
- Departamento de Biologia, Instituto de Biociências, UNESP, Rio Claro, São Paulo, CEP 13506-900, Brazil
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García-Souto D, Troncoso T, Pérez M, Pasantes JJ. Molecular Cytogenetic Analysis of the European Hake Merluccius merluccius (Merlucciidae, Gadiformes): U1 and U2 snRNA Gene Clusters Map to the Same Location. PLoS One 2015; 10:e0146150. [PMID: 26716701 PMCID: PMC4696792 DOI: 10.1371/journal.pone.0146150] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 12/13/2015] [Indexed: 01/25/2023] Open
Abstract
The European hake (Merluccius merluccius) is a highly valuable and intensely fished species in which a long-term alive stock has been established in captivity for aquaculture purposes. Due to their huge economic importance, genetic studies on hakes were mostly focused on phylogenetic and phylogeographic aspects; however chromosome numbers are still not described for any of the fifteen species in the genus Merluccius. In this work we report a chromosome number of 2n = 42 and a karyotype composed of three meta/submetacentric and 18 subtelo/telocentric chromosome pairs. Telomeric sequences appear exclusively at both ends of every single chromosome. Concerning rRNA genes, this species show a single 45S rDNA cluster at an intercalary location on the long arm of subtelocentric chromosome pair 12; the single 5S rDNA cluster is also intercalary to the long arm of chromosome pair 4. While U2 snRNA gene clusters map to a single subcentromeric position on chromosome pair 13, U1 snRNA gene clusters seem to appear on almost all chromosome pairs, but showing bigger clusters on pairs 5, 13, 16, 17 and 19. The brightest signals on pair 13 are coincident with the single U2 snRNA gene cluster signals. Therefore, the use of these probes allows the unequivocal identification of at least 7 of the chromosome pairs that compose the karyotype of Merluccius merluccius thus opening the way to integrate molecular genetics and cytological data on the study of the genome of this important species.
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Affiliation(s)
- Daniel García-Souto
- Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, Vigo, Spain
| | - Tomás Troncoso
- Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, Vigo, Spain
- Grupo de Acuicultura Marina, Centro Oceanográfico de Vigo, Instituto Español de Oceanografía, Vigo, Spain
| | - Montse Pérez
- Grupo de Acuicultura Marina, Centro Oceanográfico de Vigo, Instituto Español de Oceanografía, Vigo, Spain
| | - Juan José Pasantes
- Departamento de Bioquímica, Xenética e Inmunoloxía, Universidade de Vigo, Vigo, Spain
- * E-mail:
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Palacios-Gimenez OM, Carvalho CR, Ferrari Soares FA, Cabral-de-Mello DC. Contrasting the Chromosomal Organization of Repetitive DNAs in Two Gryllidae Crickets with Highly Divergent Karyotypes. PLoS One 2015; 10:e0143540. [PMID: 26630487 PMCID: PMC4667936 DOI: 10.1371/journal.pone.0143540] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/05/2015] [Indexed: 11/19/2022] Open
Abstract
A large percentage of eukaryotic genomes consist of repetitive DNA that plays an important role in the organization, size and evolution. In the case of crickets, chromosomal variability has been found using classical cytogenetics, but almost no information concerning the organization of their repetitive DNAs is available. To better understand the chromosomal organization and diversification of repetitive DNAs in crickets, we studied the chromosomes of two Gryllidae species with highly divergent karyotypes, i.e., 2n(♂) = 29,X0 (Gryllus assimilis) and 2n = 9, neo-X1X2Y (Eneoptera surinamensis). The analyses were performed using classical cytogenetic techniques, repetitive DNA mapping and genome-size estimation. Conserved characteristics were observed, such as the occurrence of a small number of clusters of rDNAs and U snDNAs, in contrast to the multiple clusters/dispersal of the H3 histone genes. The positions of U2 snDNA and 18S rDNA are also conserved, being intermingled within the largest autosome. The distribution and base-pair composition of the heterochromatin and repetitive DNA pools of these organisms differed, suggesting reorganization. Although the microsatellite arrays had a similar distribution pattern, being dispersed along entire chromosomes, as has been observed in some grasshopper species, a band-like pattern was also observed in the E. surinamensis chromosomes, putatively due to their amplification and clustering. In addition to these differences, the genome of E. surinamensis is approximately 2.5 times larger than that of G. assimilis, which we hypothesize is due to the amplification of repetitive DNAs. Finally, we discuss the possible involvement of repetitive DNAs in the differentiation of the neo-sex chromosomes of E. surinamensis, as has been reported in other eukaryotic groups. This study provided an opportunity to explore the evolutionary dynamics of repetitive DNAs in two non-model species and will contribute to the understanding of chromosomal evolution in a group about which little chromosomal and genomic information is known.
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Affiliation(s)
| | - Carlos Roberto Carvalho
- UFV–Univ. Federal de Viçosa, Centro de Ciências Biológicas, Departamento de Biologia Geral, Viçosa, MG, Brazil
| | | | - Diogo C. Cabral-de-Mello
- UNESP—Univ. Estadual Paulista, Instituto de Biociências/IB, Departamento de Biologia, Rio Claro, SP, Brazil
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