Chromosomal studies in four species of genus Chaunus (Bufonidae, Anura): localization of telomeric and ribosomal sequences after fluorescence in situ hybridization (FISH)

Autor(es)

Amaro-Ghilardi, Renata Cecilia ^{[1, 2]} ; de Jesus Silva, Maria Jose ^[3] ; Rodrigues, Miguel Trefaut ^[1] ; Yonenaga-Yassuda, Yatiyo ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biociencias, Dept Zool, BR-05508900 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Dept Genet & Biol Evolutiva, BR-05508900 Sao Paulo - Brazil

^[3] Inst Butantan, Genet Lab, BR-05508900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Genetica; v. 134, n. 2, p. 159-168, Oct. 2008.
• Área do conhecimento: Ciências Biológicas - Genética
• Citações Web of Science: 11
• Assunto(s): Citogenética Anfíbios

Resumo

Fluorescence in situ hybridization (FISH) using telomeric and ribosomal sequences was performed in four species of toad genus Chaunus: C. ictericus, C. jimi, C. rubescens and C. schneideri. Analyses based on conventional, C-banding and Ag-NOR staining were also carried out. The four species present a 2n = 22 karyotype, composed by metacentric and submetacentric chromosomes, which were indistinguishable either after conventional staining or banding techniques. Constitutive heterochromatin was predominantly located at pericentromeric regions, and telomeric sequences (TTAGGG)n were restricted to the end of all chromosomes. Silver staining revealed Ag-NORs located at the short arm of pair 7, and heteromorphism in size of NOR signals was also observed. By contrast, FISH with ribosomal probes clearly demonstrated absence of any heteromorphism in size of rDNA sequences, suggesting that the difference observed after Ag-staining should be attributed to differences in chromosomal condensation and/or gene activity rather than to the number of ribosomal cistrons. (AU)

• Processo FAPESP: 00/01341-6 - Citogenetica comparativa de especies da familia leptodactylidae (amphibia, anura).
• Beneficiário: Renata Cecília Amaro
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 99/11653-6 - Estudos evolutivos em vertebrados: I) análises citogenéticas, moleculares e morfológicas; II) levantamento cariotípico da fauna brasileira e III) banco de células e tecidos de mamíferos
• Beneficiário: Yatiyo Yonenaga-Yassuda
• Modalidade de apoio: Auxílio à Pesquisa - Temático