Consulta: subjectFacets:"Karyotypic evolution"
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Data/hora: 09/06/2024 16:54:02

Astyanax hastatus Myers, 1928 (Teleostei, Characidae): a new species complex within the genus Astyanax?
Provedor de dados: Genetics and Molecular Biology
Autores: Kavalco,Karine Frehner; Brandão,Karina de Oliveira; Pazza,Rubens; Almeida-Toledo,Lurdes Foresti de.
Four populations of Astyanax hastatus Myers 1928 from the Guapimirim River basin (Rio de Janeiro State) were analyzed and three distinct cytotypes identified. These cytotypes presented 2n = 50 chromosomes, with 4M+8SM+10ST+28A (Cytotype A), 8M+10SM+14ST+18A (Cytotype B), 6M+8SM+4ST+32A (Cytotype C) and scanty heterochromatin, mainly located throughout pericentromeric regions of several chromosomal pairs. No homologies with the As-51 satellite DNA were observed in the three cytotypes, although all of them presented multiple 18S rDNA sites, as detected by both silver nitrate staining and FISH (fluorescent in situ hybridization). The application of the term "species complex" in Astyanax is discussed from a cytotaxonomic viewpoint.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Astyanax hastatus; Molecular cytogenetics; Karyotypic evolution; Species complex.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000300009

Cytogenetic analysis of five species of the subfamily Corydoradinae (Teleostei: Siluriformes: Callichthyidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Shimabukuro-Dias,Cristiane Kioko; Oliveira,Claudio; Foresti,Fausto.
In the present study, five callichthyid species belonging to the subfamily Corydoradinae were karyotyped: three species of Aspidoras and two of Corydoras. The three species of Aspidoras had the same diploid number, 2n = 46 chromosomes, similar karyotypic formulae, with most chromosomes metacentric or submetacentric, single interstitial Ag-NORs and C-band positive segments mainly found in the centromeric position. The comparative analysis of cytogenetic data available for the genus Aspidoras and other species of Corydoradinae suggest that several events of centric fusion occurred in the origin of the species of Aspidoras. The two analyzed species of Corydoras showed high diploid numbers, 2n = 74 in C. sodalis and 2n = 90 in C. britskii. While C. sodalis...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fish cytogenetic; Karyotype; NOR; C-banding; Karyotypic evolution.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000400014

Chromosome characterization and variability in some Iridaceae from Northeastern Brazil
Provedor de dados: Genetics and Molecular Biology
Autores: Alves,Lânia Isis F.; Lima,Saulo Antônio A.; Felix,Leonardo P.
The chromosomes of 15 species of Iridaceae of the genera Alophia, Cipura, Eleutherine, Neomarica and Trimezia (subfamily Iridoideae) were examined after conventional Giemsa staining. The karyotypes of Alophia drummondii (2n = 14+1B, 28, 42 and 56), Cipura paludosa (2n = 14), C. xanthomelas (2n = 28) and Eleutherine bulbosa (2n = 12) were asymmetric; Neomarica candida, N. caerulea, N. humilis, N. glauca, N. gracilis, N. northiana and Neomarica sp. (2n = 18); N. cf. paradoxa (2n = 28), Trimezia fosteriana (2n = 52), T. martinicensis (2n = 54) and T. connata (2n = 82) were all generally symmetric. New diploid numbers of 2n = 56 for Alophia drummondii, 2n = 18 for N. candida, N. humilis, N. glauca, and N. gracilis, 2n = 28 for N. cf. paradoxa, and 2n = 82 for...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Iridaceae; Disploidy; Karyotypic evolution; Polyploidy; Asymmetrical karyotype.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000200016

Interspecific chromosomal divergences in the genus Characidium (Teleostei: Characiformes: Crenuchidae)
Provedor de dados: Neotropical Ichthyology
Autores: Alves,José Carlos Pansonato; Paiva,Luiz Ricardo de Souza; Oliveira,Claudio; Foresti,Fausto.
Karyotypes of seven fish species of the genus Characidium, three of them studied for the first time, were characterized using conventional cytogenetic techniques (Giemsa staining, Ag-NOR, and C-banding). All species presented a diploid number of 2n=50, with only metacentric and submetacentric chromosomes, as observed in all Characidium species studied. In two species cells with one to three B chromosomes were observed. All species analyzed have a single NOR-bearing chromosome pair with morphological differences among them. Characidium cf. zebra shows heterochromatic blocks restricted to the pericentromeric regions of all chromosomes denoting the absence of a sex chromosome system. On the other hand, the species Characidium lanei, C. pterostictum, C....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Karyotypic evolution; Sex chromosomes; B-chromosomes; Ag-NORs.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252010000100010

Evidence of separate karyotype evolutionary pathway in Euglossa orchid bees by cytogenetic analyses
Provedor de dados: Anais da Academia Brasileira de Ciências
Autores: FERNANDES,ANDERSON; WERNECK,HUGO A.; POMPOLO,SILVIA G.; LOPES,DENILCE M.
Euglossini are solitary bees considered important pollinators of many orchid species. Information regarding chromosome organization is available for only a small number of species in this group. In the present work, the species Euglossa townsendi and E. carolina were analyzed by cytogenetic techniques to collect information that may aid the understanding of their evolution and chromosomal organization. The chromosome number found was n = 21 for males and 2n = 42 for females in the two species. The distribution and amount of heterochromatin regions differed in the two species analyzed, where they were classified as “high” or “low” heterochromatin content, similarly to what has already been performed in social bee species of the genus Melipona. Banding...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cytogenetics; Euglossini; Heterochromatin; Karyotypic evolution.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652013000300937

Chromosomal studies of five species of the marine fishes from the Paranaguá Bay and the karyotypic diversity in the marine teleostei of the Brazilian coast
Provedor de dados: Brazilian Archives of Biology and Technology
Autores: Cipriano,Roger Raupp; Fenocchio,Alberto Sérgio; Artoni,Roberto Ferreira; Molina,Wagner; Noleto,Rafael Bueno; Kantek,Daniel Luis Zanella; Cestari,Marta Margarete.
In this study, five species of marine fishes from the Paranaguá Bay in the Brazilian coast were evaluated. Eucinostomus argenteus and Diapterus rhombeus (Gerreidae) presented 48 chromosomes, all of which more acrocentric (FN = 48); Strongylura timucu and S. marina (Belonidae) also presented 48 chromosomes, but with a higher karyotypic complexity than the Gerreidae, 10M+2SM+36A (FN = 60) and 4M+44A (FN = 52), respectively. The fifth species, Mugil curema (Mugilidae), different than the others, presented only 28 chromosomes 20M+4ST+4A (FN = 48). The species presented diversity in the karyotypic macro-structure, which should be relevant for the cytotaxonomy and the evolution of this group of the vertebrate.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Marine fishes; Karyotype; Cytotaxonomy; Karyotypic evolution.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000200010