Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae)
Among four specimens of Astyanax scabripinnis sympatrically collected from the Tamanduá stream (State of São Paulo, Brazil), three, named cytotype I, had 2n = 50 chromosomes (6M + 26SM + 4ST + 14A) and a fundamental number (FN) of 86, and one specimen, named cytotype II, had 2n = 48 chromosomes (6M...
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| Format: | Article |
| Language: | English |
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Sociedade Brasileira de Genética
2000-06-01
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| Series: | Genetics and Molecular Biology |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000200021 |
| _version_ | 1818385637515984896 |
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| author | Edson Luis Maistro Claudio Oliveira Fausto Foresti |
| author_facet | Edson Luis Maistro Claudio Oliveira Fausto Foresti |
| author_sort | Edson Luis Maistro |
| collection | DOAJ |
| description | Among four specimens of Astyanax scabripinnis sympatrically collected from the Tamanduá stream (State of São Paulo, Brazil), three, named cytotype I, had 2n = 50 chromosomes (6M + 26SM + 4ST + 14A) and a fundamental number (FN) of 86, and one specimen, named cytotype II, had 2n = 48 chromosomes (6M + 28SM + 4ST + 10A) and FN = 86. Besides the difference in diploid number, the cytotypes showed a clear difference in the distribution of constitutive heterochromatin. One NOR-bearing chromosome pair was detected in both cytotypes and one specimen of cytotype I had multiple NORs (tree chromosome pairs). Robertsonian translocations and an increase or loss of heterochromatin are proposed to explain the karyotypic divergence observed. Some aspects related to the chromosome evolution of Astyanax scabripinnis are discussed.<br>Foram analisados citogeneticamente quatro exemplares de Astyanax scabripinnis coletados simpatricamente no ribeirão Tamanduá (Estado de São Paulo, Brasil). Três deles, denominados de citótipo I, apresentaram 2n = 50 cromossomos (6M + 26SM + 4ST + 14A) e um número fundamental (FN) igual a 86, e um exemplar, denominado de citótipo II, apresentou 2n = 48 cromossomos (6M + 28SM + 4ST + 10A) e FN = 86. Ao lado das diferenças no número diploide, os citótipos mostraram uma clara diferença na distribuição da heterocromatina constitutiva. Um par de cromossomos portadores de RONs foi detectado nos dois citótipos e um exemplar com o citótipo I apresentou RONs múltiplas (três pares cromossômicos). Translocações Robertsonianas e aumento ou perda de heterocromatina são propostas para explicar a divergência cariotípica observada. Alguns aspectos relacionados à evolução cromossômica em Astyanax scabripinnis são discutidos. |
| first_indexed | 2024-12-14T03:41:19Z |
| format | Article |
| id | doaj.art-96e692e627c4451c890ad4b064cdd882 |
| institution | Directory Open Access Journal |
| issn | 1415-4757 1678-4685 |
| language | English |
| last_indexed | 2024-12-14T03:41:19Z |
| publishDate | 2000-06-01 |
| publisher | Sociedade Brasileira de Genética |
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| series | Genetics and Molecular Biology |
| spelling | doaj.art-96e692e627c4451c890ad4b064cdd8822022-12-21T23:18:29ZengSociedade Brasileira de GenéticaGenetics and Molecular Biology1415-47571678-46852000-06-0123236536910.1590/S1415-47572000000200021Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae)Edson Luis MaistroClaudio OliveiraFausto ForestiAmong four specimens of Astyanax scabripinnis sympatrically collected from the Tamanduá stream (State of São Paulo, Brazil), three, named cytotype I, had 2n = 50 chromosomes (6M + 26SM + 4ST + 14A) and a fundamental number (FN) of 86, and one specimen, named cytotype II, had 2n = 48 chromosomes (6M + 28SM + 4ST + 10A) and FN = 86. Besides the difference in diploid number, the cytotypes showed a clear difference in the distribution of constitutive heterochromatin. One NOR-bearing chromosome pair was detected in both cytotypes and one specimen of cytotype I had multiple NORs (tree chromosome pairs). Robertsonian translocations and an increase or loss of heterochromatin are proposed to explain the karyotypic divergence observed. Some aspects related to the chromosome evolution of Astyanax scabripinnis are discussed.<br>Foram analisados citogeneticamente quatro exemplares de Astyanax scabripinnis coletados simpatricamente no ribeirão Tamanduá (Estado de São Paulo, Brasil). Três deles, denominados de citótipo I, apresentaram 2n = 50 cromossomos (6M + 26SM + 4ST + 14A) e um número fundamental (FN) igual a 86, e um exemplar, denominado de citótipo II, apresentou 2n = 48 cromossomos (6M + 28SM + 4ST + 10A) e FN = 86. Ao lado das diferenças no número diploide, os citótipos mostraram uma clara diferença na distribuição da heterocromatina constitutiva. Um par de cromossomos portadores de RONs foi detectado nos dois citótipos e um exemplar com o citótipo I apresentou RONs múltiplas (três pares cromossômicos). Translocações Robertsonianas e aumento ou perda de heterocromatina são propostas para explicar a divergência cariotípica observada. Alguns aspectos relacionados à evolução cromossômica em Astyanax scabripinnis são discutidos.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000200021 |
| spellingShingle | Edson Luis Maistro Claudio Oliveira Fausto Foresti Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae) Genetics and Molecular Biology |
| title | Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae) |
| title_full | Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae) |
| title_fullStr | Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae) |
| title_full_unstemmed | Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae) |
| title_short | Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae) |
| title_sort | sympatric occurrence of two cytotypes of astyanax scabripinnis characiformes characidae |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000200021 |
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