Consulta: subjectFacets:"Constitutive heterochromatin"
Registros recuperados: 5
Data/hora: 10/06/2024 03:40:06

Astylus variegatus (Coleoptera, Melyridae): Cytogenetic study of a population exposed to agrochemical products
Provedor de dados: Genetics and Molecular Biology
Autores: Schneider,Marielle Cristina; Carraro,Bianca Pierina; Cella,Doralice Maria; Matiello,Rodrigo Rodrigues; Artoni,Roberto Ferreira; Almeida,Mara Cristina.
In this work we describe the cytogenetic analyses performed in specimens of Astylus variegatus (Germar, 1824) collected in two localities: one area of natural vegetation and one of agricultural crops, where agrochemical products were used. Astylus variegatus had karyotypes with 2n(male) = 16+Xy p and 2n (female) = 16+XXp, with exclusively metacentric chromosomes. Pachytene spermatocytes showed synapsed autosomal bivalents and non-associated sex chromosomes. In diplotene, the autosomal bivalents exhibited one or two terminal chiasmata and the Xy p had a typical parachute configuration. In meiotic cells of some specimens, an extra chromosome, interpreted as a B chromosome, was observed. C-banding showed constitutive heterochromatin in the pericentromeric...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: B chromosome; Constitutive heterochromatin; Karyotype; Meiosis; Ag-NORs.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400023

Comparative cytogenetic analysis of two grasshopper species of the tribe Abracrini (Ommatolampinae, Acrididae)
Provedor de dados: Genetics and Molecular Biology
Autores: Rocha,Marília de França; Melo,Natoniel Franklin de; Souza,Maria José de.
The grasshopper species Orthoscapheus rufipes and Eujivarus fusiformis were analyzed using several cytogenetic techniques. The karyotype of O. rufipes, described here for the first time, had a diploid number of 2n = 23, whereas E. fusiformis had a karyotype with 2n = 21. The two species showed the same mechanism of sex determination (XO type) but differed in chromosome morphology. Pericentromeric blocks of constitutive heterochromatin (CH) were detected in the chromosome complement of both species. CMA3/DA/DAPI staining revealed CMA3-positive blocks in CH regions in four autosomal bivalents of O. rufipes and in two of E. fusiformis. The location of active NORs differed between the two species, occurring in bivalents M6 and S9 of O. rufipes and M6 and M7 of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Constitutive heterochromatin; Fluorochromes; FISH; Orthoptera; Ribosomal DNA.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000200008

Chromosome study in Schistocerca (Orthoptera-Acrididae-Cyrtacanthacridinae): karyotypes and distribution patterns of constitutive heterochromatin and nucleolus organizer regions (NORs)
Provedor de dados: Genetics and Molecular Biology
Autores: Souza,Maria José de; Melo,Natoniel Franklin de.
Chromosome analyses were performed in two grasshopper species of the genus Schistocerca, S. pallens and S. flavofasciata. Both species shared the same diploid number (2n = 23, X in males; 2n = 24, XX in females);and a conserved karyotype composed exclusively of acrocentric chromosomes, but differed in their distribution patterns of constitutive heterochromatin and nucleolus organizer regions (NORs). Constitutive heterochromatin was located in the pericentromeric region of all chromosomes in both species. S. flavofasciata presented an additional C-band on the distal region of the long arm of a small autosome pair (S9). Nucleolus organizer regions (NORs), revealed by silver nitrate staining (Ag-NORs), were observed on a medium autosome pair (M5) in both...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Grasshopper; Constitutive heterochromatin; Nucleolus organizer regions.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000100011

Karyotype, C-and fluorescence banding pattern, NOR location and FISH study of five Scarabaeidae (Coleoptera) species
Provedor de dados: Genetics and Molecular Biology
Autores: Bione,Edgar; Moura,Rita de Cássia de; Carvalho,Reginaldo de; Souza,Maria José de.
Meiotic chromosomes obtained from members of the coleopteran subfamilies Rutelinae and Dynastinae were studied using standard and silver nitrate staining, C-banding, base-specific fluorochromes and fluorescent in situ hybridization (FISH). The study presents detailed karyotipic descripitions of three Rutelinae species (Geniates borelli, Macraspis festiva and Pelidnota pallidipennis), and two Dynastinae species (Lygirus ebenus and Strategus surinamensis hirtus) with special emphasis on the distribution and variability of constitutive heterochromatin and the nucleolar organizer region (NOR). We found that for G. borelli, P. pallidipennis, L. ebenus and S. s hirtus the karyotype was 2n = 20 (9II + Xy p), with G. borelli, P. pallidipennis and L. ebenus showed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Karyotype; Constitutive heterochromatin; NORs; RDNA sequences.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000300006

Hidden heterochromatin: characterization in the Rodentia species Cricetus cricetus, Peromyscus eremicus (Cricetidae) and Praomys tullbergi (Muridae)
Provedor de dados: Genetics and Molecular Biology
Autores: Paço,Ana; Adega,Filomena; Guedes-Pinto,Henrique; Chaves,Raquel.
The use of in situ restriction endonuclease (RE) (which cleaves DNA at specific sequences) digestion has proven to be a useful technique in improving the dissection of constitutive heterochromatin (CH), and in the understanding of the CH evolution in different genomes. In the present work we describe in detail the CH of the three Rodentia species, Cricetus cricetus, Peromyscus eremicus (family Cricetidae) and Praomys tullbergi (family Muridae) using a panel of seven REs followed by C-banding. Comparison of the amount, distribution and molecular nature of C-positive heterochromatin revealed molecular heterogeneity in the heterochromatin of the three species. The large number of subclasses of CH identified in Praomys tullbergi chromosomes indicated that the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Constitutive heterochromatin; In situ restriction endonuclease digestion; Rodentia.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000100009