title: New insights on the origin of B chromosomes in Astyanax scabripinnis obtained by chromosome painting and FISH.
abstract: Chromosome painting (CP) with a probe of B chromosome obtained by microdissection and fluorescence in situ hybridization (FISH) with probes of As51 satellite DNA, C(                            o                         )t-1 DNA, and 18S and 5S rDNA confirmed sharing of some repetitive DNA but not rDNA between A and B chromosomes in the fish Astyanax scabripinnis. Meiotic analysis revealed a pachytene B chromosome bivalent nearly half the size of its mitotic configuration, suggesting a self-pairing of B chromosome arms. Such an isochromosome nature of somatic B chromosome was further evidenced by CP and FISH. All the findings obtained suggest (i) intraspecific origin of B chromosome, and (ii) evolutionary enrichment of repetitive DNA classes, especially those contained in the C(                            o                         )t-1 and the As51 probes, in B chromosome. However, the precise origin of B chromosome in the present species remains to be elucidated by further molecular cytogenetic analysis because of painting of some A chromosome regions with the B chromosome-derived probe.
authors.affiliation: Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748, Ponta Grossa, PR 84030-900, Brazil.
authors.forename: Marcelo Ricardo
authors.initials: MR
authors.lastname: Vicari
authors.forename: Helena Flávia
authors.initials: HF
authors.lastname: de Mello Pistune
authors.forename: Jonathan Pena
authors.initials: JP
authors.lastname: Castro
authors.forename: Mara Cristina
authors.initials: MC
authors.lastname: de Almeida
authors.forename: Luiz Antonio Carlos
authors.initials: LA
authors.lastname: Bertollo
authors.forename: Orlando
authors.initials: O
authors.lastname: Moreira-Filho
authors.forename: Juan Pedro M
authors.initials: JP
authors.lastname: Camacho
authors.forename: Roberto Ferreira
authors.initials: RF
authors.lastname: Artoni
mesh_terms: D000818:Animals; D060126:Characidae / Q000235:genetics*; D020223:Chromosome Painting; D002875:Chromosomes / Q000235:genetics*; D004247:DNA / Q000235:genetics; D005260:Female; D008297:Male; D008540:Meiosis / Q000235:genetics; D008677:Metaphase / Q000235:genetics; D042282:Microdissection; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics
chemical_list: D004247:DNA