title: Mechanisms of Chromosomal Diversification in Species of Rineloricaria (Actinopterygii: Siluriformes: Loricariidae).
abstract: Cytogenetic studies in fish of the Rineloricaria genus have already shown a high variation in diploid number (2n). Along with fusion/fission events for 2n alteration, inversions contribute to the diversification of chromosome formulae within this group. The present study assessed different populations/species of the Rineloricaria aiming to describe the karyotype organization of its members and understand the mechanisms that lead to the variation of chromosome numbers. Cytogenetic data showed distinct karyotype organization among Rineloricaria populations/species studied, ranging in diploid number from 46 to 64 chromosomes, syntopic species and two karyomorphs in Rineloricaria pentamaculata. Using ribosomal DNAs (rDNAs) and TTAGGGn probes by fluorescence in situ hybridization in species with low diploid numbers, we detected sites of 18S rDNA, 5S rDNA, and TTAGGGn in centromeric regions of metacentric chromosomes, which participated in chromosome rearrangements like centric fusions. In species with high 2n, centric fissions probably occurred in karyotypic diversification. In this study, we assessed the telomeric instability, chromosomal breaks, and rearrangements due to interstitial telomeric site vestiges detection, in addition to the probable role of rDNAs in chromosome fusions in karyotypic diversification of this group.
authors.affiliation: 1 Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa , Ponta Grossa, Brazil .
authors.forename: Cleberson C
authors.initials: CC
authors.lastname: Primo
authors.affiliation: 1 Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa , Ponta Grossa, Brazil .
authors.forename: Larissa
authors.initials: L
authors.lastname: Glugoski
authors.affiliation: 1 Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa , Ponta Grossa, Brazil .
authors.forename: Mara C
authors.initials: MC
authors.lastname: Almeida
authors.affiliation: 2 Departamento de Biologia, Universidade Estadual de Maringá , Maringá, Brazil .
authors.forename: Cláudio H
authors.initials: CH
authors.lastname: Zawadzki
authors.affiliation: 3 Departamento de Genética e Evolução, Universidade Federal de São Carlos , São Carlos, Brazil .
authors.forename: Orlando
authors.initials: O
authors.lastname: Moreira-Filho
authors.affiliation: 1 Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa , Ponta Grossa, Brazil .
authors.forename: Marcelo R
authors.initials: MR
authors.lastname: Vicari
authors.affiliation: 1 Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa , Ponta Grossa, Brazil .
authors.forename: Viviane
authors.initials: V
authors.lastname: Nogaroto
mesh_terms: D000818:Animals; D002397:Catfishes / Q000235:genetics*; D002874:Chromosome Mapping / Q000379:methods*; D002875:Chromosomes / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics; D005786:Gene Expression Regulation; D014644:Genetic Variation; D017404:In Situ Hybridization, Fluorescence; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal
keywords: FISH; Robertsonian rearrangements; TTAGGGn probe; rDNAs; repetitive DNAs