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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Karyotype characterization of Crotalaria juncea (L.) by chromosome banding and physical mapping of 18S-5.8S-26S and 5S rRNA gene sites

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Author(s):
Mateus Mondin [1] ; Janay A. Santos-Serejo ; Margarida L.R. Aguiar-Perecin [3]
Total Authors: 3
Affiliation:
[1] Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz. Departamento de Genética - Brasil
[3] Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz. Departamento de Genética - Brasil
Total Affiliations: 3
Document type: Journal article
Source: GENETICS AND MOLECULAR BIOLOGY; v. 30, n. 1, p. 65-72, 2007-00-00.
Abstract

The chromosomes of Crotalaria juncea, a legume of agronomic interest with a 2n = 16 karyotype composed of metacentric chromosomes, were analyzed using several cytogenetic techniques. C-banding revealed heterochromatic regions around the centromeres in all chromosomes and adjacent to the secondary constriction on the chromosome 1 short arm. Fluorescent staining with the GC-specific chromomycin A3 (CMA) highlighted these heterochromatic regions and a tiny site on the chromosome 1 long arm while the AT-specific stain 4'-6-diamidino-2-phenylindole (DAPI) induced a reversed pattern. Staining with CMA combined with AT-specific distamycin A (DA) counterstaining quenched the pericentromeric regions of all chromosomes, but enhanced fluorescence was observed at the heterochromatic regions around the secondary constriction and on the long arms of chromosomes 1 and 4. Fluorescence in situ hybridization (FISH) revealed 18S-5.8S-26S rRNA gene sites (45S rDNA) on chromosomes 1 and 4, and one 5S rDNA locus on chromosome 1. All the rDNA sites were co-located with the positive-CMA/DA bands, suggesting they were very rich in GC. Silver staining revealed signals at the main 45S rDNA locus on chromosome 1 and, in some cells, chromosome 4 was labeled. Two small nucleoli were detected in a few interphase cells, suggesting that the minor site on chromosome 4 could be active at some stages of the cell cycle. (AU)

FAPESP's process: 98/01170-5 - Analysis of some groups of plants genome through molecular hybridization in situ techniques for mapping of repetitive sequences of DNA (FISH) and analysis of genomic DNA (GISH)
Grantee:Margarida Lopes Rodrigues de Aguiar-Perecin
Support Opportunities: Research Projects - Thematic Grants