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Made available in DSpace on 2020-12-12T01:13:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-01 Cytogenetic data showed a variation in diploid chromosome number in the genus Hyphessobrycon ranging from 2n = 46 to 52, and studies involving repetitive DNA sequences are scarce in representatives of this genus. The purpose of this paper was the chromosomal mapping of repetitive sequences (rDNA, histone genes, U snDNA and microsatellites) and investigation of the amplification of 5S rDNA clusters in the Hyphessobrycon eques genome. Two H. eques populations displayed 2n = 52 chromosomes, with the acrocentric pair No. 24 bearing Ag-NORs corresponding with CMA3+/DAPI−. FISH with a 18S rDNA probe identified the NORs on the short (p) arms of the acrocentric pairs Nos. 22 and 24. The 5S rDNA probe visualized signals on almost all chromosomes in genomes of individuals from both populations (40 signals); FISH with H3 histone probe identified two chromosome pairs, with the pericentromeric location of signals; FISH with a U2 snDNA probe identified one chromosome pair bearing signals, on the interstitial chromosomal region. The mononucleotide (A), dinucleotide (CA) and tetranucleotide (GATA) repeats were observed on the centromeric/pericentromeric and/or terminal positions of all chromosomes, while the trinucleotide (CAG) repeat showed signals on few chromosomes. Molecular analysis of 5S rDNA and non-transcribed spacers (NTS) showed microsatellites (GATA and A repeats) and a fragment of retrotransposon (SINE3/5S-Sauria) inside the sequences. This study expanded the available cytogenetic data for H. eques and demonstrated to the dispersion of the 5S rDNA sequences on almost all chromosomes. Centro de Ciências Biológicas e da Saúde Laboratório de Citogenética Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua Universitária, 2069 Universidade Estadual de Mato Grosso do Sul (UEMS) Unidade de Mundo Novo, BR 163, Km 20.2 Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), Av. 24A, 1515 Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), Av. 24A, 1515

Made available in DSpace on 2019-10-06T15:32:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-01 Astyanax is a genus with a wide distribution ranging from the south United States to north of Patagonia (Argentina). The available cytogenetic data on Astyanax indicate a high karyotypic diversity, with diploid number of 36-52 chromosomes, presence of B chromosomes, heterochromatin polymorphism, and variations with respect to the number and localization of nucleolar organizer regions (NORs) and 18S and 5S ribosomal DNA sites. In the present study, we estimated the evolutionary history and times of divergence for 10 nominal Astyanax species from the South and Central/North American (Cna) continents, which present distinct chromosomal characteristics, based on molecular clocks inferred from mitochondrial DNA sequence. The molecular clock results indicate the origin of three distinct clades (Humeral dark spot [Hds]; Diffuse humeral spot [Dhs]; Cna group) during the late Miocene about 11.2 million years ago (Mya). Thus, Astyanax mexicanus (Cna) represent a species that diverged a long time ago (∼8.6 Mya) from the Hds group, and Astyanax schubarti is the oldest species (∼6.5 Mya) among the Dhs species. Laboratório de Citogenética Departamento de Biologia Instituto de Biociências Universidade Estadual Paulista júlio de Mesquita Filho (UNESP), Avenue 24A Universidade Estadual de Mato Grosso Do sul (UEMS) Unidade de Mundo Novo Universidade Federal Do Rio de Janeiro (UFRJ) Núcleo em Ecologia e Desenvolvimento Socioambiental de Macaé (NUPEM/UFRJ) Laboratório de Genética Animal Departamento de Biologia e Zoologia Instituto de Biociências Universidade Federal de Mato Grosso (UFMT) Laboratório de Citogenética Departamento de Biologia Instituto de Biociências Universidade Estadual Paulista júlio de Mesquita Filho (UNESP), Avenue 24A

The W chromosome of Megaleporinus trifasciatus was isolated in order to analyze its behavior in the karyotype of this and other species of the family, including forms with differentiated and undifferentiated sex chromosomes. The chromosome was microdissected, and the WMt probe was prepared for the chromosome painting procedure. M. trifasciatus was also cross-hybridized (cross-FISH) using existing probes available for M. macrocephalus (WMm) and M. elongatus (WMe). Two Leporinus species and Semaprochilodus taeniurus, representing a clade close to the Anostomidae, were also cross-hybridized with the objective to better understand the evolution of the sex chromosomes. In the metaphase of female M. trifasciatus, the WMt probe highlighted the whole long arm of the W chromosome and a small, distal portion of the long arm of the Z chromosome. In males, the probe highlighted the distal portion of the long arm of the Z chromosomes. The hybridization of female M. trifasciatus with the WMe and WMm probes revealed a pattern similar to that encountered using the WMt probe. The WMt, WMm, and WMe probes revealed broad similarities among the species of the genus Megaleporinus, which has a ZZ/ZW system of sex chromosomes, with only minor alterations becoming apparent when analyzed separately.

Made available in DSpace on 2018-11-26T17:44:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The Piabina genus was allocated in Stervadiinae subfamily after staying for years as an uncertain group in Characidae. Few cytogenetic studies are described in the literature for Piabina argentea, thus new analyzes in other populations are important to understanding of the chromosomal dynamics of them. The aim of this paper was to analyze the chromosomes of P. argentea from Corumbatai River basin focusing mainly the chromosomal locations of 18S rDNA and 5S rDNA clusters. The diploid chromosome number was 2n = 52 for P. argentea, which were classified as 6 metacentrics (m), 8 submetacentrics (sm), 24 subtelocentrics (st) and 14 acrocentrics (a), and FN (fundamental number) value 90 in both sexes. Silver nitrate impregnation located the nucleolus organizer regions (Ag-NORs) on the short (p) arm of pair 16, however, an intra-individual variation of Ag-NORs sites was observed in two individuals. Fluorescence in situ hybridization (FISH) revealed six 18S rDNA sites (pairs 8, 10 and 16) and four 5S rDNA sites in terminal positions of the short arm of pairs 5 and 22 (one submetacentric and one acrocentric) in P. argentea. The results indicate that, despite the conserved diploid number, this group of fish presents a wide variability of the 18S and 5S rDNA sites. Univ Estadual Paulista, UNESP, Inst Biociencias, Dept Biol,Lab Citogenet, Av 24A,1515, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Mato Grosso do Sul UEMS, Unidade Mundo Novo, BR 163,Km 20-2, BR-79980000 Mundo Novo, MS, Brazil Univ Estadual Paulista, UNESP, Inst Biociencias, Dept Biol,Lab Citogenet, Av 24A,1515, BR-13506900 Rio Claro, SP, Brazil

Made available in DSpace on 2018-12-11T16:47:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Repetitive sequences and their chromosomal locations have been widely studied in species of the Astyanax genus. However, the chromosomal organization of U2 snDNA remains largely unknown. The aims of this study were to examine the chromosomal contexts of U2 snRNA and 5S rRNA genes in Astyanax species and determine the degree of chromosome morphological similarity between species with different diploid numbers. Clusters of U2 snDNA and 5S rDNA were determined in nine species of Astyanax, including two karyomorphs of Astyanax fasciatus Cuvier, 1819. All species exhibited U2 snDNA clusters on two chromosome pairs, except Astyanax mexicanus De Filippi, 1853 (one pair). The 5S rDNA clusters were located on one chromosome pair in Astyanax altiparanae Garutti and Britski, 2000, and Astyanax marionae Eigenmann, 1911, two pairs in Astyanax abramis Jenyns, 1842, Astyanax asuncionensis Géry, 1972, Astyanax bockmanni Vari and Castro, 2007, Astyanax eigenmanniorum Cope, 1894, A. fasciatus (karyomorphs I and II), and Astyanax schubarti Britski, 1964, and four pairs in A. mexicanus. The relationships between the repetitive sequences in different species suggest that A. schubarti and A. mexicanus exhibit an unusual U2 snDNA chromosomal format as a result of events occurring in the evolutionary history of the Astyanax group. Laboratório de Citogenética Departamento de Biologia Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Av. 24A, 1515 Laboratório de Genética Animal Departamento de Biologia e Zoologia, Universidade Federal de Mato Grosso (UFMT) Laboratório de Citogenética Departamento de Biologia Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Av. 24A, 1515

Made available in DSpace on 2018-12-11T16:41:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-17 The genus Astyanax is widely distributed from the southern United States to northern Patagonia, Argentina. While cytogenetic studies have been performed for this genus, little is known about the histone gene families. The aim of this study was to examine the chromosomal relationships among the different species of Astyanax. The chromosomal locations of the 5S rRNA and H3 histone genes were determined in A. abramis, A. asuncionensis, A. altiparanae, A. bockmanni, A. eigenmanniorum, A. mexicanus (all 2n = 50), A. fasciatus (2n = 46), and A. schubarti (2n = 36). All eight species exhibited H3 histone clusters on two chromosome pairs. In six species (A. abramis, A. asuncionensis, A. altiparanae, A. bockmanni, A. eigenmanniorum, and A. fasciatus), syntenic clusters of H3 histone and 5S rDNA were observed on metacentric (m) or submetacentric (sm) chromosomes. In seven species, clusters of 5S rDNA sequences were located on one or two chromosome pairs. In A. mexicanus, 5S rDNA clusters were located on four chromosome pairs. This study demonstrates that H3 histone clusters are conserved on two chromosome pairs in the genus Astyanax, and specific chromosomal features may contribute to the genomic organization of the H3 histone and 5S rRNA genes. Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Av. 24A, 1515 Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Av. 24A, 1515

The organization of microsatellites in B and sex chromosomes has been linked to chromosomal evolution in a number of animal groups. Here, the chromosomal organizations of (CA)15, (GA)15, (CG)15, (GACA)4, and (GATA)8 microsatellites were examined in several Astyanax species with different diploid numbers: Astyanax mexicanus (2n = 50 + 1 B chromosome), A. altiparanae (2n = 50), A. marionae (2n = 48), A. fasciatus (2n = 46), and A. schubarti (2n = 36). The (CA)15 and (GA)15 microsatellites were dispersed across the chromosomes of A. altiparanae and A. fasciatus but were also observed as clusters (CA and GA for A. altiparanae, and CA for A. fasciatus). In A. marionae and A. schubarti, the (CA)15 and (GA)15 microsatellites were dispersed but were also observed as clustered signals and coincident with heterochromatic regions. In all 4 of these species, the (CG)15 and (GACA)4 microsatellites were dispersed across chromosomes, and the (GATA)8 microsatellite was co-localized with 5S rDNA. In A. mexicanus, the (CA)15, (GA)15, (CG)15, (GATA)8, and (GACA)4 microsatellites were weakly detected and dispersed across the chromosomes of the A complement. On the B chromosome, signals for the different microsatellites were weak, strong, absent, weak, and absent, respectively. The distribution of microsatellites and the locational relationship between microsatellites and 5S rDNA are discussed, and a possible evolutionary pathway is proposed for microsatellites in Astyanax.

Made available in DSpace on 2018-12-11T16:52:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The U small nuclear RNA (U snRNA) genes comprise a multigene family and are required for splicing of pre-mRNA. In this paper, we aimed to study the chromosomal location of the U2 snRNA gene in Megaleporinus, Leporinus and Schizodon species, which constitute interesting models for the study of repetitive DNA and genomic evolution in fish once the group comprises species with and without heteromorphic sex chromosomes. The all six species showed 2n = 54 chromosomes: Megaleporinus elongatus, Megaleporinus macrocephalus, Leporinus striatus, Leporinus friderici, Schizodon borelli and Schizodon isognathus. The U2 snDNA clusters were evident in only one medium-sized submetracentric pair in all analyzed species and this may represent a condition shared by Anostomidae family. Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), Av. 24A, 1515 Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), Av. 24A, 1515 FAPESP: 10/10/51339-0

The W chromosome of Megaleporinus trifasciatus was isolated in order to analyze its behavior in the karyotype of this and other species of the family, including forms with differentiated and undifferentiated sex chromosomes. The chromosome was microdissected, and the WMt probe was prepared for the chromosome painting procedure. M. trifasciatus was also cross-hybridized (cross-FISH) using existing probes available for M. macrocephalus (WMm) and M. elongatus (WMe). Two Leporinus species and Semaprochilodus taeniurus, representing a clade close to the Anostomidae, were also cross-hybridized with the objective to better understand the evolution of the sex chromosomes. In the metaphase of female M. trifasciatus, the WMt probe highlighted the whole long arm of the W chromosome and a small, distal portion of the long arm of the Z chromosome. In males, the probe highlighted the distal portion of the long arm of the Z chromosomes. The hybridization of female M. trifasciatus with the WMe and WMm probes revealed a pattern similar to that encountered using the WMt probe. The WMt, WMm, and WMe probes revealed broad similarities among the species of the genus Megaleporinus, which has a ZZ/ZW system of sex chromosomes, with only minor alterations becoming apparent when analyzed separately.

Made available in DSpace on 2018-12-11T16:51:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-02 The cytogenetic studies of retrotranposons Rex have been characterized in several fish groups, including species of the Astyanax genus. This group presents an extensive variability in their karyotype, with diploid numbers of 2n = 52, 50, 48, 46 and 36 chromosomes. Thus, the aim of this study was to evaluate the distribution of the retrotransposable element Rex1, in six Astyanax species, with different diploid numbers. The species analyzed were Astyanax altiparanae (2n = 50), Astyanax asuncionensis (2n = 50), Astyanax eigenmanniorum (2n = 50), Astyanax marionae (2n = 48), Astyanax fasciatus (2n = 46) and Astyanax schubarti (2n = 36). Rex1 was dispersed in the Astyanax species, suggesting that these retrotransposons play important role in genome evolution. Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP) Instituto de Biociências Departamento de Biologia e Zoologia Laboratório de Genética Animal Universidade Federal de Mato Grosso (UFMT) Instituto Federal de Educação Ciência e Tecnologia do Piauí (IFPI) Laboratório de Biologia Instituto de Biociências Departamento de Biologia Laboratório de Citogenética Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP)

The Hyphessobrycon are allocated in the incertae sedis group of the Characidae family, one of the genera with more species of the group. The chromosomes of some species of Hyphessobrycon are known, and the diploid number most common for genus is 2n = 50 chromosomes. The aims of this study were to examine the karyotype macrostructure in the Hyphessobrycon eques Steindachner, 1882, and show a new origin hypothesis for B chromosomes. The diploid number observed for Hyphessobrycon eques was 2n = 52 chromosomes, and a karyotype formulae of 12m + 18sm + 8st + 14a, with FN (fundamental number) = 90 for both sexes. Only two females showed one B chromosome. The heterochromatin was observed mainly on centromeric regions, and in the long arm of the B chromosome. In this paper, the relationship of the B chromosome of Hyphessobrycon eques with an occasional chromosome rearrangement was discussed.

Made available in DSpace on 2015-10-21T13:12:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The species of genus Astyanax is widely distributed in freshwater neotropical zones. Astyanax is considered to be taxonomically confused, similar to other genera placed incertae sedis in Characidae. The cytogenetics of this genus is well characterized; species vary widely in diploid number, from 2n=36 chromosomes in Astyanax schubarti to 2n=50 for most species studied. The size, number, and position of different cytological markers vary among species and populations of Astyanax. We analyzed the karyotypes of individuals from three Astyanax species (Astyanax abramis, Astyanax altiparanae, and Astyanax eigenmanniorum) from populations not previously analyzed. We describe variations in several cytogenetic markers and the karyotypic relationships between them, specifically focusing on the characteristics of the conserved and divergent locations of the ribosomal genes. Our data are useful for establishing relationships between species and for investigating the karyotype evolution within the genus. Universidade Estadual Paulista ‘‘Júlio de Mesquita Filho’’ (UNESP) - Laboratório de Citogenética, Departamento de Biologia, Instituto de Biociências, Rio Claro, São Paulo, Brasil. Empresa Brasileira de Pesquisa Agropecuária (Embrapa) Pesca e Aquicultura (CNPASA), Palmas, Tocantins, Brasil Universidade Estadual Paulista ‘‘Júlio de Mesquita Filho’’ (UNESP) - Laboratório de Citogenética, Departamento de Biologia, Instituto de Biociências, Rio Claro, São Paulo, Brasil.

Made available in DSpace on 2014-12-03T13:11:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-04-01Bitstream added on 2014-12-03T13:22:50Z : No. of bitstreams: 1 WOS000317829800001.pdf: 597255 bytes, checksum: d596e504ddd65c823178cb74e22b9092 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Background: Nowadays, the genus Bryconamericus is placed in subfamily Stevardiinae within of Characidae, but not shows consistent evidence of monophyletism. The purpose of this work was to study the chromosomes of three species of Bryconamericus, aiming to add cytogenetic knowledge and contribute to the understanding of the chromosomal evolution of this genus.Results: The chromosomes of three species of Bryconamericus were analyzed using cytogenetic techniques. The karyotype of Bryconamericus stramineus contained 6 metacentric (m) + 10 submetacentric (sm) + 16 subtelocentric (st) + 20 acrocentric (a), the fundamental number (FN) of 84, one silver impregnated (Ag-NOR) pair, one pair bearing the 18S ribosomal DNA sites, another pair bearing the 5S rDNA sites, and a few positive C-bands. Bryconamericus turiuba had a karyotype containing 8 m + 10sm + 14st + 20a (FN = 84), one chromosome pair Ag-NOR, two pairs bearing the 18S rDNA sites, two pairs bearing the 5S rDNA sites, and a few C-band regions. Bryconamericus cf. iheringii had a karyotype containing 10 m + 14sm + 18st + 10a (FN = 94), including one pair with a secondary constriction Ag-NOR positive. In this karyotype the fluorescent in situ hybridization (FISH) showed the 18S and 5S rDNA probe in adjacent position.Conclusions: The results obtained in this work showed different characteristics in the organization of two multigene families, indicating that distinct evolutionary forces acting on the diversity of rDNA sequences in the genome of three Bryconamericus species. Univ Estadual Paulista Julio Mesquita Filho UNESP, Inst Biociencias, Dept Biol, Lab Citogenet, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Mato Grosso Sul UEMS, BR-79980000 Mundo Novo, MS, Brazil Univ Estadual Paulista Julio Mesquita Filho UNESP, Inst Biociencias, Dept Biol, Lab Citogenet, BR-13506900 Rio Claro, SP, Brazil