title: Whole chromosome painting of B chromosomes of the red-eye tetra Moenkhausia sanctaefilomenae (Teleostei, Characidae).
abstract: B chromosomes are dispensable genomic elements found in different groups of animals and plants. In the present study, a whole chromosome probe was generated from a specific heterochromatic B chromosome occurring in cells of the characidae fish Moenkhausia sanctaefilomenae (Steindachner, 1907). The chromosome painting probes were used in fluorescence in situ hybridization (FISH) experiments for the assessment of metaphase chromosomes obtained from individuals from three populations of Moenkhausia sanctaefilomenae. The results revealed that DNA sequences were shared between a specific B chromosome and many chromosomes of the A complement in all populations analyzed, suggesting a possible intra-specific origin of these B chromosomes. However, no hybridization signals were observed in other B chromosomes found in the same individuals, implying a possible independent origin of B chromosome variants in this species. FISH experiments using 18S rDNA probes revealed the presence of non-active ribosomal genes in some B chromosomes and in some chromosomes of the A complement, suggesting that at least two types of B chromosomes had an independent origin. The role of heterochromatic segments and ribosomal sequences in the origin of B chromosomes were discussed.
authors.affiliation: Universidade Estadual Paulista (UNESP), Instituto de Biociências de Botucatu, Laboratório de Biologia e Genética de Peixes, Departamento de Morfologia, Distrito de Rubião Junior, 18618-970, Botucatu, São Paulo, Brazil.
authors.forename: Patricia Elda Sobrinho
authors.initials: PE
authors.lastname: Scudeler
authors.affiliation: Universidade Estadual do Sudoeste da Bahia (UESB), Departamento de Ciências Biológicas (DCB), Rua José Moreira Sobrinho s/n, 45206-190, Jequié, Bahia, Brazil.
authors.forename: Débora
authors.initials: D
authors.lastname: Diniz
authors.affiliation: Universidade Estadual Paulista (UNESP), Instituto de Biociências de Botucatu, Departamento de Genética, Distrito de Rubião Junior, 18618-970, Botucatu, São Paulo, Brazil.
authors.forename: Adriane Pinto
authors.initials: AP
authors.lastname: Wasko
authors.affiliation: Universidade Estadual do Sudoeste da Bahia (UESB), Departamento de Ciências Biológicas (DCB), Rua José Moreira Sobrinho s/n, 45206-190, Jequié, Bahia, Brazil.
authors.forename: Claudio
authors.initials: C
authors.lastname: Oliveira
authors.affiliation: Universidade Estadual Paulista (UNESP), Instituto de Biociências de Botucatu, Laboratório de Biologia e Genética de Peixes, Departamento de Morfologia, Distrito de Rubião Junior, 18618-970, Botucatu, São Paulo, Brazil.
authors.forename: Fausto
authors.initials: F
authors.lastname: Foresti
keywords: Chromosomal evolution; Chromosome microdissection; Chromosome painting; Genome organization; Repetitive DNA