Data/hora: 09/06/2024 05:30:10

Provedor de dados: | Genetics and Molecular Biology
País: | Brazil
Título: | Chromatin differentiation between Theobroma cacao L. and T. grandiflorum Schum
Autores: | Dantas,Liliane G.; Guerra,Marcelo.
Data: | 2010-01-01
Ano: | 2010
Palavras-chave: | Cacao; Cupuaçu; Heterochromatin; Karyotype; RDNA sites; Theobroma.
Resumo: | A comparative analysis of mitotic chromosomes of Theobroma cacao (cacao) and T. grandiflorum (cupuaçu) was performed aiming to identify cytological differences between the two most important species of this genus. Both species have symmetric karyotypes, with 2n = 20 metacentric chromosomes ranging in size from 2.00 to 1.19 µm (cacao) and from 2.21 to 1.15 mm (cupuaçu). The interphase nuclei of both species were of the arreticulate type, displaying up to 20 chromocentres, which were more regularly shaped in cacao than in cupuaçu. Prophase chromosomes of both species were more condensed in the proximal region, sometimes including the whole short arm. Both species exhibited only one pair of terminal heterochromatic bands, positively stained with chromomycin A3, which co-localized with the single 45S rDNA site. Each karyotype displayed a single 5S rDNA site in the proximal region of another chromosome pair. Heterochromatic bands were also observed on the centromeric/pericentromeric regions of all 20 chromosomes of cacao after C-banding followed by Giemsa or DAPI staining, whereas in cupuaçu they were never detected. These data suggest that the chromosomes of both species have been largely conserved and their pericentromeric chromatin is the only citologically differentiated region.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000100017
Editor: | Sociedade Brasileira de Genética
Relação: | 10.1590/S1415-47572009005000103
Formato: | text/html
Fonte: | Genetics and Molecular Biology  v.33 n.1 2010
Fonte: | info:eu-repo/semantics/openAccess