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| Registros recuperados: 16 | |
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| Guerra,Marcelo. |
| Abstract Agmatoploidy is a type of chromosome rearrangement that involves the fragmentation of an entire chromosome complement, generating a diploid with double its original chromosome number. Agmatoploidy and other related karyotype changes, such as symploidy (the opposite change, promoted by chromosome fusion), partial agmatoploidy, polyagmatoploidy, etc., are restricted to species with holokinetic chromosomes and are assumed to play an important role in their karyotype evolution. However, a critical review of the literature shows that examples of chromosome number doubling by agmatoploidy are rare and not clearly demonstrated, while partial agmatoploidy and partial symploidy seem to be the same as ascending and descending disploidy, respectively. It is... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agmatoploidy; Symploidy; Holocentrics; Holokinetic chromosomes; Chromosome evolution. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572016000400492 |
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| Svartman,Marta. |
| Marsupials, one of the three main groups of mammals, are only found in Australia and in the American continent. Studies performed in Australian marsupials have demonstrated the great potential provided by the group for the understanding of basic genetic mechanisms and chromosome evolution in mammals. Genetic studies in American marsupials are relatively scarce and cytogenetic data of most species are restricted to karyotype descriptions, usually without banding patterns. Nevertheless, the first marsupial genome sequenced was that of Monodelphis domestica, a South American species. The knowledge about mammalian genome evolution and function that resulted from studies on M. domestica is in sharp contrast with the lack of genetic data on most American... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Marsupials; Cytogenetics; Chromosome evolution. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000400002 |
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| Arcanjo,Amanda; Cabral-de-Mello,Diogo Cavalcanti; Martins,Cesar; Moura,Rita de Cássia de; Souza,Maria José de. |
| The genus Phanaeus is included in the tribe Phanaeini, one of the most diverse tribes within the subfamily Scarabaeinae in terms of chromosomal characteristics. However, so far the species of this genus were not studied with differential cytogenetic techniques, limiting any inference of the probable mechanisms responsible for this diversity. In this work, several techniques were applied with the aim of cytogenetically characterizing two Phanaeus species. The karyotype found for Phanaeus (Notiophanaeus) chalcomelas was 2n = 12, neo-XY, and that of P. (N.) splendidulus was 2n = 20, Xy p, considered primitive for the family Scarabaeidae. The chromosomes of both species showed a high amount of constitutive heterochromatin (CH), with blocks rich in base pairs... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Karyotype; Chromosome evolution; Repetitive DNA; FISH. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572013000300007 |
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| Rocha,Érika Cruz; Molina,Wagner Franco. |
| The Lutjanidae or snappers are a family of perciform fishes, mainly marine but with some members living in estuaries and entering fresh water to feed. Some are important food fish. Cytogenetic data for Lutjanidae are scarce. In the present work, we cytogenetically characterized through conventional Giemsa staining techniques, Ag-NOR and C-banding the species Ocyurus chrysurus, Lutjanus analis, L. alexandrei, L. cyanopterus, L. jocu and L. synagris, all found along the Brazilian coast. Karyotype analysis of all six species showed a modal value of 2n = 48 acrocentric chromosomes. Single NORs were found at pericentromeric position on the long arms of the 2nd pair in O. chrysurus, L. alexandrei and L. cyanopterus, on the 5th pair in L. analis and on the 23rd... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome evolution; Fish cytogenetics; Lutjanidae; Lutjanus; Ocyurus. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000300011 |
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| Nirchio,Mauro; Martinez,Emanuel Ricardo Monteiro; Foresti,Fausto; Oliveira,Claudio. |
| Despite their ecological and economical importance, fishes of the family Ariidae are still genetically and cytogenetically poorly studied. Among the 133 known species of ariids, only eight have been karyotyped. Cytogenetic analyses performed on Genidens barbus and Sciades herzbergii revealed that both species have 2n = 56 chromosomes and Cathorops aff. mapale has 2n = 52 chromosomes: Genidens barbus has 10 Metacentrics (M), 14 Submetacentrics (SM), 26 Subtelocentrics (ST), and 6 Acrocentrics (A), Sciades herzbergii has 14M, 20SM, 18ST and 4A, whereas Cathorops aff. mapale has 14M, 20SM, and 18ST. The nucleolus organizer regions (NORs) were found in a single chromosome pair on the short arm of a large-sized ST pair in Genidens barbus and on the short arm of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cytogenetics; Ag-NORs; Chromosome evolution; Chromosome rearrangements; Fish. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000200011 |
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| Vicari,Marcelo Ricardo; Pazza,Rubens; Artoni,Roberto Ferreira; Margarido,Vladimir Pavan; Bertollo,Luiz Antonio Carlos. |
| Hoplias malabaricus (trahyra) is a widespread fish species over the Neotropical region with diversified inter-populational karyotypes (cytotypes), which may correspond to a species complex. Despite the wide distribution in the South American basins, some authors have questioned its natural origin in the Iguaçu river, an important Brazilian river basin which is characterized by several endemic fish species. We have analyzed the karyotype of H. malabaricus from different collection sites of this river, by conventional and banding methods. Our results, in addition to our previous data concerning geographic distribution of the cytotypes, contribute to better understand the origin of H. malabaricus on the Iguaçu river, reinforcing the proposition that it is a... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome evolution; Karyotypes distribution; Endemism. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000300015 |
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| Sato,Luciana Ramos; Oliveira,Claudio; Foresti,Fausto. |
| Trichomycteridae is a family of small catfish which are widely distributed throughout Southern Central America and South America. The present study showed that the cis-Andean species Trichomycterus florensis, Trichomycterus sp. aff. Trichomycterus itatiyae, Trichomycterus reinhardti, Trichomycterus davisi and Trichomycterus auroguttatus had 2n = 54 chromosomes (42 metacentric, 10 submetacentric and 2 subtelocentric), with T. reinhardti, T. auroguttatus and T. sp. aff. T. itatiyae exhibiting only one chromosome pair with silver-stained nucleolus organizer regions (NORs). The cytogenetic data suggest the existence of at least two groups of species in the cis-Andean representatives of the genus Trichomycterus. In the first group the first metacentric pair is... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome evolution; NOR banding; Fish. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000100008 |
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| Degrandi,Tiago Marafiga; Gunski,Ricardo José; Garnero,Analía del Valle; Oliveira,Edivaldo Herculano Correa de; Kretschmer,Rafael; Souza,Marcelo Santos de; Barcellos,Suziane Alves; Hass,Iris. |
| Abstract The distribution of 45S rDNA cluster in avian karyotypes varies in different aspects, such as position, number of bearer chromosomes, and bearers being macro- or microchromosomes. The present study investigated the patterns of variation in the 45S rDNA-bearer chromosomes of birds in order to understand the evolutionary dynamics of the cluster configuration and its contribution to the evolution of bird karyotypes. A total of 73 bird species were analyzed, including both published data and species for which rDNA-FISH was conducted for the first time. In most birds, the 45S rDNA clusters were located in a single pair of microchromosomes. Hence, the location of 45S rDNA in macrochromosomes, observed only in Neognathae species, seems to be a derived... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: FISH; Chromosome; Chromosome evolution; Cytogenetics; Aves. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572020000400601 |
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| Registros recuperados: 16 | |
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