title: Identification and chromosome mapping of repetitive elements in the Astyanax scabripinnis (Teleostei: Characidae) species complex.
abstract: Most part of the eukaryotic genome is composed of repeated sequences or multiple copies of DNA, which were considered as "junk DNA", and may be associated to the heterochromatin. In this study, three populations of Astyanax aff. scabripinnis from Brazilian rivers of Guaratinguetá and Pindamonhangaba (São Paulo) and a population from Maringá (Paraná) were analyzed concerning the localization of the nucleolar organizer regions (Ag-NORs), the As51 satellite DNA, the 18S ribosomal DNA (rDNA), and the 5S rDNA. Repeated sequences were also isolated and identified by the Cot - 1 method, which indicated similarity (90%) with the LINE UnaL2 retrotransposon. The fluorescence in situ hybridization (FISH) showed the retrotransposon dispersed and more concentrated markers in centromeric and telomeric chromosomal regions. These sequences were co-localized and interspaced with 18S and 5S rDNA and As51, confirmed by fiber-FISH essay. The B chromosome found in these populations pointed to a conspicuous hybridization with LINE probe, which is also co-located in As51 sequences. The NORs were active at unique sites of a homologous pair in the three populations. There were no evidences that transposable elements and repetitive DNA had influence in the transcriptional regulation of ribosomal genes in our analyses.
authors.affiliation: Programa de Pós Graduação em Biologia Evolutiva, Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Avenida Carlos Cavalcanti 4748, Ponta Grossa, PR, 84030-900, Brazil.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Barbosa
authors.forename: Luiz Antonio
authors.initials: LA
authors.lastname: de Oliveira
authors.forename: Marcela Baer
authors.initials: MB
authors.lastname: Pucci
authors.forename: Mateus Henrique
authors.initials: MH
authors.lastname: Santos
authors.forename: Orlando
authors.initials: O
authors.lastname: Moreira-Filho
authors.forename: Marcelo Ricardo
authors.initials: MR
authors.lastname: Vicari
authors.forename: Viviane
authors.initials: V
authors.lastname: Nogaroto
authors.forename: Mara Cristina
authors.initials: MC
authors.lastname: de Almeida
authors.forename: Roberto Ferreira
authors.initials: RF
authors.lastname: Artoni
mesh_terms: D000818:Animals; D001483:Base Sequence; D060126:Characidae / Q000235:genetics*; D002874:Chromosome Mapping; D004276:DNA, Satellite; D005260:Female; D005828:Genetics, Population; D017404:In Situ Hybridization, Fluorescence; D020084:Long Interspersed Nucleotide Elements; D008297:Male; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid; D016415:Sequence Alignment
chemical_list: D004276:DNA, Satellite