Data/hora: 10/06/2024 01:03:19

Provedor de dados: 	74	
País: 	Brazil	
Título: 	Astylus variegatus (Coleoptera, Melyridae): Cytogenetic study of a population exposed to agrochemical products	
Autores: 	Schneider,Marielle Cristina; Carraro,Bianca Pierina; Cella,Doralice Maria; Matiello,Rodrigo Rodrigues; Artoni,Roberto Ferreira; Almeida,Mara Cristina.	
Data: 	2007-01-01	
Ano: 	2007	
Palavras-chave: 	B chromosome; Constitutive heterochromatin; Karyotype; Meiosis; Ag-NORs.	
Resumo: 	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 region of all chromosomes, with the exception of the y p. Silver nitrate staining revealed one nucleolus organizer region (NOR) on the terminal region of the short arm of the second autosome pair. Silver staining of meiotic cells confirmed the NOR pattern detected in mitotic cells and revealed an argentophilous material on the Xy p. A cytogenetic comparison between the two populations of A. variegatus showed a statistically significant divergence (chi2 = 117.10; df = 1) in the number of aneuploid cells and a higher frequency of B chromosome in the population exposed to agrochemicals.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400023	
Editor: 	Sociedade Brasileira de Genética	
Relação: 	10.1590/S1415-47572007000400023	
Formato: 	text/html	
Fonte: 	Genetics and Molecular Biology  v.30 n.3 2007	
Fonte: 	info:eu-repo/semantics/openAccess