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Localization of rDNA sites in holocentric chromosomes of three species of triatomines (Heteroptera, Triatominae)
Grasiela Dias de Campos Severi-Aguiar and Maria Tercília Vilela de Azeredo-Oliveira
Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas,
IBILCE-UNESP, 15054-000 São José do Rio Preto, SP, Brasil
Corresponding author: G.D.C. Severi-Aguiar
E-mail: [email protected]
Genet. Mol. Res. 4 (4): 704-709 (2005)
Received March 12, 2005
Accepted September 19, 2005
Published November 29, 2005

ABSTRACT. Chromatin organization in the holocentric chromosomes of three triatomines species was cytologically studied by fluorescent in situ hybridization with a 45S rDNA probe of Drosophila melanogaster to localize ribosomal genes. In Triatoma tibiamaculata, metaphases I showed telomeric highlights in a single, larger bivalent. In T. protacta, hybridization was detected in one of the telomeres of an autosomal chromosome. In T. platensis, there were highlights in a single, smaller chromosome (X chromosome). The results obtained did not agree with the expected localization of rDNA genes in the sex chromosomes of triatomines, as demonstrated by silver impregnation, and suggest that the chromosome reorganization that occurred in this group during evolution may be a more important mechanism involved in rDNA distribution.

Key words: Fluorescent in situ hybridization, Holocentric chromosomes, Nucleolar organizer region, Heteroptera, Triatominae


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