Use este identificador para citar ou linkar para este item: https://locus.ufv.br//handle/123456789/26587
Tipo: Artigo
Título: C-banding and fluorescent in situ hybridization with rDNA sequences in chromosomes of Cycloneda sanguinea Linnaeus (Coleoptera, Coccinellidae)
Autor(es): Pompolo, Silvia das Graças
Maffei, Eliane Mariza Dortas
Petitpierre, Eduard
Abstract: The aim of this study was to describe mitotic and meiotic chromosomes of Cycloneda sanguinea using C-banding, fluorescent in situ hybridization (FISH) rDNA probes, and sequential FISH/Ag-NOR staining. The chromosome number was 2n = 18 + XX for females and 2n = 18 + Xy for males. The X chromosome was metacentric and the Y chromosome was very small. During meiosis, the karyotypic meioformula was n = 9 + Xyp, and sex chromosomes configured a parachute at metaphase I. At the beginning of pachytene, bivalents were still individualized, and sex chromosomes were associated end-to-end through the heteropycnotic region of the X chromosome. Later in pachytene, further condensation led to the formation of a pseudo-ring by the sex bivalent. All chromosomes showed pericentromeric heterochromatin. FISH and sequential FISH/Ag-NOR staining evidenced the location of the nucleolar organizer region in one pair of autosomes (at spermatogonial metaphase). During meiosis, these genes were mapped to a region outside the sex vesicle by FISH, although Xyp was deeply stained with silver at metaphase I. These results suggest that these argyrophilic substances are of a nucleolar protein nature, and seem to be synthesized by a pair of autosomes and imported during meiosis (prophase I) to the sex pair, during the association of the sex chromosomes.
Palavras-chave: In situ hybridization
rDNA sequences
Sequential FISH/Ag-NOR staining
C-banding
Cycloneda sanguinea
Editor: Genetics and Molecular Biology
Tipo de Acesso: Open Access
URI: http://dx.doi.org/10.1590/S1415-47572004000200011
https://locus.ufv.br//handle/123456789/26587
Data do documento: 2004
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