Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)

Species of the subtribe Oedionychina not only have a highly uniform diploid number of 2n = 22 (20+X+y) but have the karyotypic peculiarity of possessing extremely large sex chromosomes. We analyzed Paranaita opima embryos and gonadal cells to determine their diploid number, chromosomal morphology, t...

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Main Authors: Mara Cristina de Almeida, Carlos Campaner, Doralice Maria Cella
Format: Article
Language:English
Published: Sociedade Brasileira de Genética 2006-01-01
Series:Genetics and Molecular Biology
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000300013
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author Mara Cristina de Almeida
Carlos Campaner
Doralice Maria Cella
author_facet Mara Cristina de Almeida
Carlos Campaner
Doralice Maria Cella
author_sort Mara Cristina de Almeida
collection DOAJ
description Species of the subtribe Oedionychina not only have a highly uniform diploid number of 2n = 22 (20+X+y) but have the karyotypic peculiarity of possessing extremely large sex chromosomes. We analyzed Paranaita opima embryos and gonadal cells to determine their diploid number, chromosomal morphology, type of sex determination system, constitutive heterochromatin pattern and which chromosomes bear nucleolus organizer regions (NORs). The diploid number of P. opima was 2n = 22 (20+XY/XX) with all chromosomes being metacentric. Chromosome pair 6 showed an interstitial secondary constriction on the short arm. The C-banding technique revealed centromeric constitutive heterochromatin in all chromosomes, which, in pair 6, extended up to the secondary constriction of the short arm, additional C-bands also being present on the Y chromosome. Silver nitrate nucleolar organizer region (Ag-NOR) staining showed NORs on the secondary constriction of pair 6. Fluorochrome analysis with chromomycin A3 (CMA3), 4'-6-diamidino-2-phenylindole (DAPI) and the distamycin A (DA) counterstain showed that the short arm of chromosome pair 6 exhibited a GC-rich block extending from the proximal to the median region, including part of the secondary constriction. The same techniques also showed AT-rich blocks at the centromeric region of all chromosomes and at the terminal region of the short arm of pair 6. The basic karyotype characteristics and C band pattern of P. opima are similar to those described for other species in the subtribe Oedionychina. The pattern of autosomal NORs observed in P. opima corresponds to that registered in the majority of the Chrysomelidae species.
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spelling doaj.art-d88b10d6c13e48648fb2c08d1a1912e12022-12-21T17:57:27ZengSociedade Brasileira de GenéticaGenetics and Molecular Biology1415-47571678-46852006-01-0129347548110.1590/S1415-47572006000300013Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)Mara Cristina de AlmeidaCarlos CampanerDoralice Maria CellaSpecies of the subtribe Oedionychina not only have a highly uniform diploid number of 2n = 22 (20+X+y) but have the karyotypic peculiarity of possessing extremely large sex chromosomes. We analyzed Paranaita opima embryos and gonadal cells to determine their diploid number, chromosomal morphology, type of sex determination system, constitutive heterochromatin pattern and which chromosomes bear nucleolus organizer regions (NORs). The diploid number of P. opima was 2n = 22 (20+XY/XX) with all chromosomes being metacentric. Chromosome pair 6 showed an interstitial secondary constriction on the short arm. The C-banding technique revealed centromeric constitutive heterochromatin in all chromosomes, which, in pair 6, extended up to the secondary constriction of the short arm, additional C-bands also being present on the Y chromosome. Silver nitrate nucleolar organizer region (Ag-NOR) staining showed NORs on the secondary constriction of pair 6. Fluorochrome analysis with chromomycin A3 (CMA3), 4'-6-diamidino-2-phenylindole (DAPI) and the distamycin A (DA) counterstain showed that the short arm of chromosome pair 6 exhibited a GC-rich block extending from the proximal to the median region, including part of the secondary constriction. The same techniques also showed AT-rich blocks at the centromeric region of all chromosomes and at the terminal region of the short arm of pair 6. The basic karyotype characteristics and C band pattern of P. opima are similar to those described for other species in the subtribe Oedionychina. The pattern of autosomal NORs observed in P. opima corresponds to that registered in the majority of the Chrysomelidae species.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000300013C bandschromosomeembryosfluorochromesNOR
spellingShingle Mara Cristina de Almeida
Carlos Campaner
Doralice Maria Cella
Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)
Genetics and Molecular Biology
C bands
chromosome
embryos
fluorochromes
NOR
title Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)
title_full Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)
title_fullStr Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)
title_full_unstemmed Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)
title_short Karyotype characterization, constitutive heterochromatin and nucleolus organizer regions of Paranaita opima (Coleoptera, Chrysomelidae, Alticinae)
title_sort karyotype characterization constitutive heterochromatin and nucleolus organizer regions of paranaita opima coleoptera chrysomelidae alticinae
topic C bands
chromosome
embryos
fluorochromes
NOR
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000300013
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