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Mousavi SE, Grützner F, Patil JG. Enhanced mitotic arrest and chromosome resolution for cytogenetic analysis in the eastern mosquitofish, Gambusia holbrooki. Acta Histochem 2023; 125:152029. [PMID: 37062122 DOI: 10.1016/j.acthis.2023.152029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/18/2023]
Abstract
Maximising the number of cells arrested at metaphase and their resolution is fundamentally important for molecular cytogenetic investigations, particularly in fish, which typically yield low mitotic index and have highly condensed chromosomes. To overcome these limitations, fish were injected with a mitotic stimulator (the yeast, Saccharomyces cerevisiae) to improve the mitotic index, and the intercalating agent ethidium bromide to produce elongated chromosomes. Specifically, adults were injected with activated yeast and then Colcemid (0.025 µg/µl solution, 10 µl per 1 g of body weight) at 24-96 h post yeast injections, followed by chromosome preparations from multiple tissues. Results showed that gill tissue had the highest number of dividing cells at 72 h post yeast exposure with no significant (p > 0.05) differences between the sexes. Nonetheless, sex-specific differences in the mitotic index were observed in spleen, kidney, and liver, which may be attributed to sex-specific differences in immune responses. For elongation of mitotic chromosomes, individuals (both sexes) were first injected with activated yeast and after 48 h with ethidium bromide (2 or 4 µg/ml) and Colcemid (0.05 µg/µl solution, 10 µl per 1 g of body weight). Following which, animals were sampled at three time points (1, 4 and 8 h) for chromosome preparations. The results show that the optimum elongation of metaphase chromosomes of males and females was achieved by using 2 µg/ml and 4 µg/ml, respectively, for 1 h. Interestingly, the average mitotic chromosome length (μm) of males and females post-ethidium bromide exposure was significantly different (p < 0.05) for both concentrations, except at 1 h exposure for 2 µg/ml EtBr. Such differences can be attributed to overall chromosomal condensation differences between sexes. Regardless, the increased mitotic index and chromosome resolution could benefit cytogenetic studies in other fish species.
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Affiliation(s)
- Seyed Ehsan Mousavi
- Laboratory of Molecular Biology, Institute for Marine and Antarctic Studies, University of Tasmania, Taroona, TAS 7053, Australia; School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia.
| | - Frank Grützner
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Jawahar G Patil
- Laboratory of Molecular Biology, Institute for Marine and Antarctic Studies, University of Tasmania, Taroona, TAS 7053, Australia
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2
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Goes CAG, Daniel SN, Piva LH, Yasui GS, Artoni RF, Hashimoto DT, Foresti F, Porto-Foresti F. Cytogenetic markers as a tool for characterization of hybrids of Astyanax Baird & Girard, 1854 and Hyphessobrycon Eigenmann, 1907. COMPARATIVE CYTOGENETICS 2020; 14:231-242. [PMID: 32537093 PMCID: PMC7270076 DOI: 10.3897/compcytogen.v14i2.49513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Astyanax Baird et Girard, 1854, is one of the largest genera in the family Characidae and comprises 177 valid species. This genus has been the focus of cytogenetic studies primarily owing to the presence of B chromosomes and high karyotypic diversity among different populations. The intense genetic variability in Astyanax is one of the factors responsible for the occurrence of species complexes, which are groups (1) with certain difficulties in establishing common genetic pools or (2) belonging to different cryptic species. To evaluate cytogenetic marker inheritance and the possibility of the identification of these hybrids, this study aimed to describe cytogenetic hybrids from three strains of species of the genera Astyanax and Hyphessobrycon Eigenmann, 1908. A. lacustris Lütken, 1875, A. schubarti Britski, 1964, A. fasciatus Cuvier, 1819, and H. anisitsi Eigenmann, 1907 were used to generate three hybrid lineages. The diploid number, heterochromatin sites, and ribosomal genes (18S and 5S rDNA) of the parental strains and the hybrids were analyzed. The results indicated that the three hybrid lineages had cytogenetic markers of both parents, presenting Mendelian inheritance. However, differences in distribution of heterochromatic blocks were observed between the hybrids and the parent strains. Our results allowed the identification of the hybrid strains based on the cytogenetic markers applied, reinforcing the efficiency of cytogenetic markers as tools for identification and indicating that such events may increase the karyotypic diversity in the genera Astyanax and Hyphessobrycon.
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Affiliation(s)
- Caio Augusto Gomes Goes
- Universidade Estadual Paulista (UNESP) “Júlio de Mesquita Filho”, Faculdade de Ciências, Edmundo Carrijo Coube Avenue, Bauru, SP, BrazilUniversidade Estadual PaulistaBauruBrazil
| | - Sandro Natal Daniel
- Universidade Estadual Paulista (UNESP) “Júlio de Mesquita Filho”, Faculdade de Ciências, Edmundo Carrijo Coube Avenue, Bauru, SP, BrazilUniversidade Estadual PaulistaBauruBrazil
| | - Lucas Henrique Piva
- Centro nacional de Pesquisa e Conservação da Biota Aquática Continental (CEPTA-ICMBIO), Prefeito Euberto Nemésio Pereira Godói Highway, Pirassununga, SP, BrazilCentro nacional de Pesquisa e Conservação da Biota Aquática ContinentalPirassunungaBrazil
| | - George Shigueki Yasui
- Centro nacional de Pesquisa e Conservação da Biota Aquática Continental (CEPTA-ICMBIO), Prefeito Euberto Nemésio Pereira Godói Highway, Pirassununga, SP, BrazilCentro nacional de Pesquisa e Conservação da Biota Aquática ContinentalPirassunungaBrazil
| | - Roberto Ferreira Artoni
- Universidade Estadual de Ponta Grossa, Setor de Ciências Biológicas e da Saúde, Santos Andrade Square, Ponta Grossa, PR, BrazilUniversidade Estadual de Ponta GrossaPonta GrossaBrazil
| | - Diogo Teruo Hashimoto
- Universidade Estadual Paulista (UNESP) “Júlio de Mesquita Filho”, Centro de Aquicultura da UNESP, Prof. Paulo Donato Castelane Acess way, Jaboticabal, SP, BrazilUniversidade Estadual PaulistaJaboticabalBrazil
| | - Fausto Foresti
- Universidade Estadual Paulista (UNESP) “Júlio de Mesquita Filho”, Instituto de Biociências, Prof. Montenegro Avenue, Botucatu, SP, BrazilUniversidade Estadual PaulistaBotucatuBrazil
| | - Fábio Porto-Foresti
- Universidade Estadual Paulista (UNESP) “Júlio de Mesquita Filho”, Faculdade de Ciências, Edmundo Carrijo Coube Avenue, Bauru, SP, BrazilUniversidade Estadual PaulistaBauruBrazil
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Grabowska AI, Boroń A, Kirtiklis L, Spóz A, Juchno D, Kotusz J. Chromosomal inheritance of parental rDNAs distribution pattern detected by FISH in diploid F 1 hybrid progeny of Cobitis (Teleostei, Cobitidae) species has non-Mendelian character. JOURNAL OF FISH BIOLOGY 2020; 96:261-273. [PMID: 31755097 DOI: 10.1111/jfb.14216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/21/2019] [Indexed: 06/10/2023]
Abstract
This study was conducted to describe the major and the minor rDNA chromosome distribution in the spined loach Cobitis taenia (2n = 48) and the Danubian loach Cobitis elongatoides (2n = 50), and their laboratory-produced diploid reciprocal F1 hybrid progeny. It was tested by fluorescence in situ hybridisation (FISH) whether the number of 28s and 5s rDNA sites in the karyotypes of diploid hybrids corresponds to the expectations resulting from Mendelian ratio and if nucleolar organiser regions (NOR)were inherited from both parents or nucleolar dominance can be observed in the induced F1 hybrid progeny. Ten (females) or twelve (males) 28s rDNA loci were located in nine uniarm chromosomes of C. taenia. Two of such loci terminally bounded on one acrocentric chromosome were unique and indicated as specific for this species. Large 5s rDNA clusters were located on two acrocentric chromosomes. In C. elongatoides of both sexes, six NOR sites in terminal regions on six meta-submetacentric chromosomes and two 5s rDNA sites on large submetacentrics were detected. The F1 hybrid progeny (2n = 49) was characterised by the intermediate karyotype with the sites of ribosome synthesis on chromosomes inherited from both parents without showing nucleolar dominance. 5s rDNA sites were detected on large submetacentric and two acrocentric chromosomes. The observed number of both 28s and 5s rDNAs signals in F1 diploid Cobitis hybrids was disproportionally inherited from the two parental species, showing inconsistency with the Mendelian ratios. The presented rDNA patterns indicate some marker chromosomes that allow the species of the parental male and female to be recognised in hybrid progeny. The 5s rDNA was found to be a particularly effective diagnostic marker of C. elongatoides to partially discern genomic composition of diploid Cobitis hybrids and presumably allopolyploids resulting from their backcrossing with one of the parental species. Thus, the current study provides insight into the extent of rDNA heredity in Cobitis chromosomes and their cytotaxonomic character.
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Affiliation(s)
- Anna I Grabowska
- Department of Zoology, University of Warmia and Mazury, Olsztyn, Poland
| | - Alicja Boroń
- Department of Zoology, University of Warmia and Mazury, Olsztyn, Poland
| | - Lech Kirtiklis
- Department of Zoology, University of Warmia and Mazury, Olsztyn, Poland
| | - Aneta Spóz
- Department of Zoology, University of Warmia and Mazury, Olsztyn, Poland
| | - Dorota Juchno
- Department of Zoology, University of Warmia and Mazury, Olsztyn, Poland
| | - Jan Kotusz
- Museum of Natural History, University of Wroclaw, Wroclaw, Poland
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Utsunomia R, Silva DMZDA, Ruiz-Ruano FJ, Goes CAG, Melo S, Ramos LP, Oliveira C, Porto-Foresti F, Foresti F, Hashimoto DT. Satellitome landscape analysis of Megaleporinus macrocephalus (Teleostei, Anostomidae) reveals intense accumulation of satellite sequences on the heteromorphic sex chromosome. Sci Rep 2019; 9:5856. [PMID: 30971780 PMCID: PMC6458115 DOI: 10.1038/s41598-019-42383-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 03/26/2019] [Indexed: 11/09/2022] Open
Abstract
The accumulation of repetitive DNA sequences on the sex-limited W or Y chromosomes is a well-known process that is likely triggered by the suppression of recombination between the sex chromosomes, which leads to major differences in their sizes and genetic content. Here, we report an analysis conducted on the satellitome of Megaleporinus macrocephalus that focuses specifically on the satDNAs that have been shown to have higher abundances in females and are putatively located on the W chromosome in this species. We characterized 164 satellite families in M. macrocephalus, which is, by far, the most satellite-rich species discovered to date. Subsequently, we mapped 30 satellites, 22 of which were located on the W chromosome, and 14 were shown to exist only on the W chromosome. Finally, we report two simple, quick and reliable methods that can be used for sex identification in M. macrocephalus individuals using fin clips or scales, which could be applicable to future studies conducted in the field of aquaculture.
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Affiliation(s)
- Ricardo Utsunomia
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior, s/n, 18618-970, Botucatu, SP, Brazil. .,Departamento de Genética, Universidad de Granada, 18071, Granada, Spain.
| | | | | | - Caio Augusto Gomes Goes
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista - UNESP, Campus de Bauru, 17033-360, Bauru, SP, Brazil
| | - Silvana Melo
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior, s/n, 18618-970, Botucatu, SP, Brazil
| | - Lucas Peres Ramos
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior, s/n, 18618-970, Botucatu, SP, Brazil
| | - Claudio Oliveira
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior, s/n, 18618-970, Botucatu, SP, Brazil
| | - Fábio Porto-Foresti
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista - UNESP, Campus de Bauru, 17033-360, Bauru, SP, Brazil
| | - Fausto Foresti
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista - UNESP, Distrito de Rubião Junior, s/n, 18618-970, Botucatu, SP, Brazil
| | - Diogo Teruo Hashimoto
- CAUNESP, Universidade Estadual Paulista - UNESP, Campus Jaboticabal, 14884-900, Jaboticabal, SP, Brazil
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Ribeiro LB, Moraes Neto A, Artoni RF, Matoso DA, Feldberg E. Chromosomal Mapping of Repetitive Sequences (Rex3, Rex6, and rDNA Genes) in Hybrids Between Colossoma macropomum (Cuvier, 1818) and Piaractus mesopotamicus (Holmberg, 1887). Zebrafish 2017; 14:155-160. [PMID: 28067606 DOI: 10.1089/zeb.2016.1378] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Some species of Characiformes are known for their high economic value, such as Colossoma macropomum and Piaractus mesopotamicus, and are used in aquaculture programs to generate hybrid tambacu (interbreeding of C. macropomum females and P. mesopotamicus males). The present work aimed to investigate the location of the Rex3 and Rex6 transposable elements in the hybrid and in the species, in addition to checking the genomic organization of the 18S and 5S rDNA in tambacu. The diploid number found for the hybrid was equal to 54 chromosomes, with heterochromatic blocks distributed mainly in the centromeric portions. The chromosomal location of the mobile elements Rex3 and Rex6 in C. macropomum, P. mesopotamicus, and in the hybrid between these species enabled knowledge expansion and the generation of data on such mobile elements. In addition, the location of such elements is not related to the distribution of ribosomal DNA sites. The mapping of the 18S rDNA was shown to be effective in cytogenetic identification of the hybrid tambacu, allowing for differentiation from the parent species and from the hybrid between C. macropomum and the other species from Piaractus (P. brachypomus).
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Affiliation(s)
- Leila Braga Ribeiro
- 1 Centro de Ciências da Saúde, Universidade Federal de Roraima (UFRR) , Boa Vista, Brazil
| | - Americo Moraes Neto
- 2 Programa de Pós-Graduação em Ciência Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso do Sul (UFMS) , Campo Grande, Brazil
| | - Roberto Ferreira Artoni
- 3 Programa de Pós-Graduação em Biologia Evolutiva, Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa (UEPG) , Ponta Grossa, Brazil
| | | | - Eliana Feldberg
- 5 Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA) , Manaus, Brazil
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Utsunomia R, Pansonato-Alves JC, Costa-Silva GJ, Mendonça FF, Scacchetti PC, Oliveira C, Foresti F. Molecular and cytogenetic analyses of cryptic species within the Synbranchus marmoratus Bloch, 1795 (Synbranchiformes: Synbranchidae) grouping: species delimitations, karyotypic evolution and intraspecific diversification. NEOTROPICAL ICHTHYOLOGY 2015. [DOI: 10.1590/1982-0224-20140039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The fish species Synbranchus marmoratushas been reported to exist as a species complex due to high intraspecific karyotypic variability in spite of the difficulty or impossibility to distinguish them using morphological traits alone. The goal of this work was to use cytogenetic and molecular methods to determine the species delimitations and understand the karyoevolution ofS. marmoratususing samples collected from distinct Brazilian localities. Among the analyzed specimens, a large degree of cytogenetic variation related to diploid numbers and karyotype structure was observed, with karyotypes showing 2n=42, 44 and 46 chromosomes. In addition, using sequences of three mitochondrial genes, the phylogenetic relationships between every sample with a known karyotype were determined, which revealed significant nucleotide divergence among the karyomorphs. Also, the analyses indicate that chromosomal rearrangements occurred independently within the distinct lineages of S. marmoratuscomplex, which resulted in the appearance of distinct karyotypic variants in a non-linear fashion related to diploid numbers and in the appearance of similar non-homologous chromosomes. Finally, the integration of both molecular cytogenetic and phylogenetic approaches allowed the determination of specific chromosomes possibly involved in rearrangements and a better understanding about the evolutionary processes involved in the differentiation ofSynbranchusgenus.
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Kitanova M, Georgiev S. Transcriptional Activity of Translocated NORs in Barley (Hordeum Vulgare L.). BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/bbeq.2011.0157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Meglena Kitanova
- Sofia University “St. Kliment Ohridski”, Faculty of Biology, Sofia, Bulgaria
| | - Sevdalin Georgiev
- Sofia University “St. Kliment Ohridski”, Faculty of Biology, Sofia, Bulgaria
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Hashimoto DT, Senhorini JA, Foresti F, Martínez P, Porto-Foresti F. Genetic identification of F1 and post-F1 serrasalmid juvenile hybrids in Brazilian aquaculture. PLoS One 2014; 9:e89902. [PMID: 24594674 PMCID: PMC3940687 DOI: 10.1371/journal.pone.0089902] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 01/29/2014] [Indexed: 11/18/2022] Open
Abstract
Juvenile fish trade monitoring is an important task on Brazilian fish farms. However, the identification of juvenile fish through morphological analysis is not feasible, particularly between interspecific hybrids and pure species individuals, making the monitoring of these individuals difficult. Hybrids can be erroneously identified as pure species in breeding facilities, which might reduce production on farms and negatively affect native populations due to escapes or stocking practices. In the present study, we used a multi-approach analysis (molecular and cytogenetic markers) to identify juveniles of three serrasalmid species (Colossoma macropomum, Piaractus mesopotamicus and Piaractus brachypomus) and their hybrids in different stocks purchased from three seed producers in Brazil. The main findings of this study were the detection of intergenus backcrossing between the hybrid ♀ patinga (P. mesopotamicus×P. brachypomus)×♂ C. macropomum and the occurrence of one hybrid triploid individual. This atypical specimen might result from automixis, a mechanism that produces unreduced gametes in some organisms. Moreover, molecular identification indicated that hybrid individuals are traded as pure species or other types of interspecific hybrids, particularly post-F1 individuals. These results show that serrasalmid fish genomes exhibit high genetic heterogeneity, and multi-approach methods and regulators could improve the surveillance of the production and trade of fish species and their hybrids, thereby facilitating the sustainable development of fish farming.
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Affiliation(s)
- Diogo Teruo Hashimoto
- Centro de Aquicultura, Universidade Estadual Paulista, (UNESP), Campus de Jaboticabal, Jaboticabal, SP, Brazil
- * E-mail:
| | - José Augusto Senhorini
- Centro de Pesquisa e Gestão de Recursos Pesqueiros Continentais, Instituto Chico Mendes de Conservação da Biodiversidade, Pirassununga, SP, Brazil
| | - Fausto Foresti
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista, (UNESP), Campus de Botucatu, Botucatu, SP, Brazil
| | - Paulino Martínez
- Departamento de Genética, Universidad de Santiago de Compostela, Facultad de Veterinaria, Lugo, Spain
| | - Fábio Porto-Foresti
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista, (UNESP), Campus de Bauru, Bauru, SP, Brazil
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Hashimoto D, Ferguson-Smith M, Rens W, Prado F, Foresti F, Porto-Foresti F. Cytogenetic Mapping of H1 Histone and Ribosomal RNA Genes in Hybrids between Catfish SpeciesPseudoplatystoma corruscansandPseudoplatystoma reticulatum. Cytogenet Genome Res 2013. [DOI: 10.1159/000345299] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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10
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Voltolin DTHTA, Paes ADNVDA, Foresti F, Bortolozzi J, Porto-Foresti F. Cytogenetic analysis of B chromosomes in one population of the fish Moenkhausia sanctaefilomenae (Steindachner, 1907) (Teleostei, Characiformes). COMPARATIVE CYTOGENETICS 2012; 6:141-51. [PMID: 24260658 PMCID: PMC3833789 DOI: 10.3897/compcytogen.v6i2.1769] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Accepted: 03/07/2012] [Indexed: 05/25/2023]
Abstract
The aim of this study was to characterize cytogenetically one population of the fish Moenkhausia sanctaefilomenae (Steindachner, 1907), with emphasis on the analysis of B chromosomes. The nucleolar activity in the B microchromosomes was characterized, and an analysis of mitotic instability of these microchromosomes was accomplished. The results showed a diploid chromosome number of 50 chromosomes. In all individuals, we observed the presence of B microchromosomes with intra- and inter-individual variability. The analysis of the nucleolus organizing regions (NORs) by silver nitrate staining demonstrated multiple NORs. We observed active sites of ribosomal DNA in the B microchromosomes, with a frequency of 20% in the analyzed cells, which shows gene activity in these chromosomal elements. The analysis of constitutive heterochromatin patterns showed that the B microchromosomes are heterochromatic or euchromatic, which demonstrates differentiation of DNA composition between these genomic elements. The calculation of the mitotic instability index implied that B chromosomes in this species might be in a final stage of instability.
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Affiliation(s)
| | | | - Fausto Foresti
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Dist. Rubião Júnior, 18618-000, Botucatu, SP, Brazil
| | - Jehud Bortolozzi
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista (UNESP), Av. Eng. Luiz E. C. Coube, 17033-360, Bauru, SP, Brazil
| | - Fábio Porto-Foresti
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista (UNESP), Av. Eng. Luiz E. C. Coube, 17033-360, Bauru, SP, Brazil
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do Prado FD, Nunes TL, Senhorini JA, Bortolozzi J, Foresti F, Porto-Foresti F. Cytogenetic characterization of F1, F2 and backcross hybrids of the Neotropical catfish species Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Pimelodidae, Siluriformes). Genet Mol Biol 2012; 35:57-64. [PMID: 22481875 PMCID: PMC3313517 DOI: 10.1590/s1415-47572012005000010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 09/21/2011] [Indexed: 11/22/2022] Open
Abstract
The cytogenetic characteristics of Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum and their F1, F2 and backcross hybrids were assessed by using chromosome banding techniques. The diploid number of 56 chromosomes was constant in all species and lineages, with a karyotypic formula containing 20 metacentric, 12 submetacentric, 12 subtelocentric and 12 acrocentric chromosomes. Nucleolar organizer regions (NORs) were identified in two subtelocentric chromosomes in the parents and hybrids, with partial nucleolar dominance in F1 and F2 specimens. Heterochromatic blocks were detected in the terminal and centromeric regions of some chromosomes in all individuals. For parental and hybrid lineages, 18S ribosomal clusters corresponding to NORs and 5S ribosomal genes were identified in distinct pairs of chromosomes. The striking conservation in the chromosomal macrostructure of the parental species may account for the fertility of their F1 hybrids. Similarly, the lack of marked alterations in the chromosomal structure of the F1 hybrids could account for the maintenance of these features in post-F1 lineages.
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Affiliation(s)
- Fernanda Dotti do Prado
- Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista "Júlio de Mesquita Filho", Bauru, SP, Brazil
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