Localization of rDNA sites in holocentric chromosomes of three species of triatomines (Heteroptera, Triatominae).

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.

Differential characterization of holocentric chromosomes in triatomines (Heteroptera, Triatominae) using different staining techniques and fluorescent in situ hybridization

A comparative study of holocentric chromosomes in the triatomine species Panstrongylus megistus, Rhodnius pallescens and Triatoma infestans was carried out in order to characterize heterochromatin, rDNA active sites and nucleolar proteins. Cytological preparations of seminiferous tubules were stained by silver impregnation, C banding, fluorochromes CMA 3/DA and DAPI/DA, and fluorescent in situ hybridization (FISH) with Drosophila melanogaster 28S rDNA probe. Our results showed interesting aspects of the organization of chromatin and chromosomes in the meiotic cells of these insects. In R. pallescens, sex chromosomes (X, Y) were distinct from autosomes, when submitted to silver impregnation, C banding, CMA 3 staining, and FISH, confirming that these chromosomes bear nucleolar organizer regions (NORs). In P. megistus, two of the three sex chromosomes were CMA 3/DAPI-; at early meiotic prophase and at diakinesis, silver impregnation corresponded with FISH signals, indicating that in this species, two chromosomes (probably a sex chromosome and an autosome) bear NORs. In T. infestans, silver nitrate and FISH also stained corresponding areas on meiotic chromosomes. Our data suggest that in triatomines, in general, the number and location of NORs are species-specific. These regions may be considered important chromosome markers for comparative studies to improve the understanding of evolutionary mechanisms in these hematophagous insects. ©FUNPEC-RP.

Análise citogenética molecular em túbulos seminíferos de triatomíneos (Triatominae, Heteroptera)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise da ocorrência de transposição em regiões reguladoras dos genes da família Cyp em espécies de Drosophila

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Elementos de transposição no gênero Zaprionus (Diptera, Drosophilidae): estudos genômicos e evolutivos em ênfase nos retrotensposons copia, gypsy e micropia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise de sequências da região intergência ITS-1 do rDNA em espécies de Drosophila do cluster buzzatti, (complexo Buzzatti, subgrupo Mullerri, grupo Repleta). -

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genomic regions harboring insecticide resistance-associated Cyp genes are enriched by transposable element fragments carrying putative transcription factor binding sites in two sibling Drosophila species

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Specific Activation of an I-Like Element in Drosophila Interspecific Hybrids

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tropical Africa as a cradle for horizontal transfers of transposable elements between species of the genus Drosophila and Zaprionus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Produtividade em espécies de Drosophila do subgrupo saltans (grupo saltans, subgênero Sophophora): efeitos da infecção por Wolbachia em linhagens normais e introgredidas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)