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Título: | Epifluorescence and light microscopy evidencing structural and functional polymorphism of ribosomal DNA in fish (Teleostei: Astyanax fasciatus) |
Autor: | Artoni, Roberto Ferreira Gross, Maria Claudia Schneider, Carlos Henrique Vicari, Marcelo Ricardo Almeida, Mara Cristina de Matoso, D. A. |
Palavras-chave: | Chlorine Compounds Location Nucleic Acids Organic Acids Population Statistics Silver Astyanax Biotinylated Epifluorescence Fish Fish Analysis Gene Activities Gene Structures In-cell Karyotype Diversification Light Microscopy Physical Mapping Population Variations Ribosomal Dna Transposable Elements Chromosomes Ribosome Dna Animals Chemistry Chromosome Map Chromosome Nor Female Fish In Situ Hybridization, Fluorescence Microscopy, Fluorescence Polymorphism, Genetic Genetics Male Physiology Ultrastructure Animal Ribosomal Dna Female Fishes In Situ Hybridization, Fluorescence Male Microscopy, Fluorescence Nucleolus Organizer Region Physical Chromosome Mapping Polymorphism, Genetic Astyanax Fasciatus Teleostei |
Data do documento: | 2008 |
Revista: | Micron |
É parte de: | Volume 39, Número 8, Pags. 1156-1159 |
Abstract: | New karyotypic data are presented for the Astyanax fasciatus species complex from four different locations on the Upper Tibagi River in the state of Paraná, Brazil. Chromosome markers were analyzed using conventional (Ag-NOR) and molecular (FISH with 18S biotinylated probes) methods. Two cytotypes were found in cell counts with diploid number 2n = 48 chromosomes and 2n = 50 chromosomes, previously denominated Cytotype A and B, respectively. Two specific patterns of Ag-NORs markers (ribosomal gene activity) were found, with intra-population and inter-population variations. Cytotype A exhibited two to three chromosomes with NOR sites in the metaphases analyzed. In Cytotype B specimens, up to three markers were found, demonstrating greater intra-population and inter-population variation. All individuals with only one chromosome pair with NORs were located in the telomeric region of the short arm of Chromosome 5. This characteristic was interpreted as ancestral for the species. Another identified pattern revealed a site in the telomeric region probably in the long arm of Chromosome 4 and another submetacentric chromosome with bitelomeric marks exclusively in specimens with 2n = 50 chromosomes. In the FISH analysis (ribosomal gene structure), five to seven markers were identified in Cytotype A and three to seven markers were identified in Cytotype B. Structural chromosome events and/or transposable elements are required to explain the ribosomal gene location diversity in these organisms. The results of the present study corroborate the hypothesis that the A. fasciatus of the Upper Tibagi River region constitute a species complex. © 2008 Elsevier Ltd. All rights reserved. |
DOI: | 10.1016/j.micron.2008.05.011 |
Aparece nas coleções: | Artigos |
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