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Your search keyword '"Oliveira, Claudio"' showing total 31 results
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31 results on '"Oliveira, Claudio"'

18. Chromosomal organization of repetitive DNA sequences in Astyanax bockmanni (Teleostei, Characiformes): dispersive location, association and co-localization in the genome

Author

Silva, Duílio M. Z. A., primary, Pansonato-Alves, José Carlos, additional, Utsunomia, Ricardo, additional, Daniel, Sandro Natal, additional, Hashimoto, Diogo Teruo, additional, Oliveira, Claudio, additional, Porto-Foresti, Fabio, additional, and Foresti, Fausto, additional

Published
2013
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23. Extensive spreading of interstitial telomeric sites on the chromosomes of Characidium (Teleostei, Characiformes).

Author

Scacchetti, Priscilla, Utsunomia, Ricardo, Pansonato-Alves, José, Costa-Silva, Guilherme, Oliveira, Claudio, and Foresti, Fausto

Abstract

Characidium comprises several species of small freshwater fish that display conserved diploid chromosome numbers and karyotypic formulae. In this study, a comparative cytogenetic analysis using telomeric DNA probes was carried out in nine species of Characidium; a molecular phylogenetic analysis with mitochondrial DNA was also performed in order to investigate the direction of the evolutionary chromosome changes observed here. Our results showed the existence of species with several and variable interstitial telomeric sites (ITSs), with other species showing only terminal signals in their chromosomes. Molecular phylogenetic data suggested that these ITSs emerged once in the evolutionary history of Characidium and were later differentially spread in distinct species/populations of this clade. Additionally, the origin of an exclusive acrocentric pair found in C. pterostictum, C. serrano and C. timbuiense was also investigated, revealing that this pair possibly had a common origin to these species. These results evidence the occurrence of intense and continuous genomic changes among species of Characidium. [ABSTRACT FROM AUTHOR]

Published
2015
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28. Isolation and Characterization of a Satellite DNA Family in Achirus lineatus (Teleostei: Pleuronectiformes: Achiridae)

Author

Azevedo, Marisa, Oliveira, Claudio, Martins, Cesar, Wasko, Adriane, and Foresti, Fausto

Abstract

Agarose gels stained with Ethidium bromide and Southern blot experiments of HindIII-digested genomic DNA of Achirus lineatus evidenced the presence of monomers and multimers of a DNA segment of about 200 bp, named here Al-HindIII sequence. No signals were observed in Southern blot experiments with genomic DNA of other flatfish species. The DNA sequencing of four recombinant clones showed that Al-HindIII sequences had 204 bp and were 63.72% AT-rich. FISH experiments using a Al-HindIII sequence as probe showed bright signals in the centromeric position of all chromosomes of A. lineatus.

Published
2005
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29. Chromosome Banding and 18S rDNA in situ Hybridization Analysis of Seven Species of the Family Achiridae (Teleostei: Pleuronectiformes)

Author

Azevedo, Marisa, Oliveira, Claudio, Pardo, Belén, Martínez, Paulino, and Foresti, Fausto

Abstract

Achiridae is an important family of the order Pleuronectiformes widely distributed in North, Central, and South America with freshwater and marine species. In the present study cytogenetic analyses comprising conventional and molecular techniques were carried out in seven species of this family. The following diploid numbers (2n) and fundamental numbers (FN) were obtained: Achirus declivis 2n = 34, FN  = 52; Achirus lineatus 2n = 40, FN  = 66; Catathyridium jenynsi 2n = 40 and FN  = 50; Gymnachirus nudus 2n = 36 and FN  = 50; Hypoclinemus mentalis 2n = 38 and FN  = 54; Trinectes paulistanus 2n = 42 and FN  = 52; and Trinectes sp. 2n = 38 and FN  = 54. All species presented a single nucleolar organizer region (NOR) bearing chromosome pair and C-band positive segments mainly distributed at the pericentromeric position. The wide variation observed in chromosome number and FN suggests the occurrence of larger chromosome rearrangements in the family Achiridae if compared with other families of the same order.

Published
2005
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30. A Natural Triploid in Trichomycterus Davisi(Siluriformes, Trichomycteridae): Mitotic and Meiotic Characterization by Chromosome Banding and Synaptonemal Complex Analyses

Author

Borin, Luciana, Martins-Santos, Isabel, and Oliveira, Claudio

Abstract

Within a total of 50 analyzed specimens a male individual of Trichomycterus davisihas been recorded with 81 chromosomes including 60 metacentric, 18 submetacentric and three subtelocentric chromosomes. When compared with diploid individuals (2n= 54) and the morphological standard of chromosomes, this male is a triploid with 3n= 81 chromosomes. Since staining with silver nitrate indicates three active nucleolar organizer regions (NORs), the three NOR-bearing chromosomes in this individual are genetically active. Analysis of the synaptonemal complex (SC) by electronic microscopy shows that there is an incomplete pairing of the third set of chromosomes in the triploid individual.

Published
2002
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31. Chromosome banding and 18S rDNA in situ hybridization analysis of seven species of the family Achiridae (Teleostei: Pleuronectiformes).

Author

Carvalho de Azevedo MF, Oliveira C, Pardo BG, Martínez P, and Foresti F

Subjects
Animals, Chromosome Banding, Diploidy, Female, In Situ Hybridization, Karyotyping, Male, Nucleolus Organizer Region genetics, RNA, Ribosomal, 18S genetics, Species Specificity, DNA, Ribosomal genetics, Flatfishes genetics
Abstract

Achiridae is an important family of the order Pleuronectiformes widely distributed in North, Central, and South America with freshwater and marine species. In the present study cytogenetic analyses comprising conventional and molecular techniques were carried out in seven species of this family. The following diploid numbers (2n) and fundamental numbers (FN) were obtained: Achirus declivis 2n=34, FN=52; Achirus lineatus 2n=40, FN=66; Catathyridium jenynsi 2n=40 and FN=50; Gymnachirus nudus 2n=36 and FN=50; Hypoclinemus mentalis 2n=38 and FN=54; Trinectes paulistanus 2n=42 and FN=52; and Trinectes sp. 2n=38 and FN=54. All species presented a single nucleolar organizer region (NOR) bearing chromosome pair and C-band positive segments mainly distributed at the pericentromeric position. The wide variation observed in chromosome number and FN suggests the occurrence of larger chromosome rearrangements in the family Achiridae if compared with other families of the same order.

Published
2005
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