title: Differentiation of repetitive DNA sites and sex chromosome systems reveal closely related group in Parodontidae (Actinopterygii: Characiformes).
abstract: Parodon and Apareiodon lack sufficiently consistent morphological traits to be considered a monophyletic group in Parodontidae. Species within this family are either sex-homomorphic or sex-heteromorphic (i.e., lacking a differentiated sex chromosome system, ZZ/ZW or ZZ/ZW(1)W(2)). In this study, a DNA fragment from the heterochromatin segment of the W chromosome of Apareiodon ibitiensis (named WAp) was microdissected and used for in situ mapping of nine Parodontidae species. The species were also characterized using a satellite DNA probe (pPh2004). The species were phylogenetically clustered according to 17 characters, which were examined by both classical and molecular cytogenetic techniques. Given the present results, the single ZZ/ZW sex chromosome system seems to have been derived from a paracentric inversion of a terminal WAp site onto the proximal regions of the short arms of a metacentric chromosome pair, followed by WAp site amplification. We reason that these events restrained recombination and favored differentiation of the W chromosome in some species. Moreover, co-hybridization experiments targeting the WAp and pPh2004 repetitive DNA sites of A. affinis suggest that the ZZ/ZW(1)W(2) sex chromosomes of this species may have arisen from a translocation between the proto-sex chromosome and an autosome. Our phylogenetic analysis corroborates the hypothesis of sex chromosome differentiation and establishes groups of closely related species. The phylogenetic reorganization in response to these new data supports the presence of internal monophyletic groups within Parodontidae.
authors.affiliation: Programa de Pós-Graduação em Biologia Evolutiva, Laboratório de Citogenética e Evolução, Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti 4748, Ponta Grossa, PR, Brazil.
authors.forename: Michelle Orane
authors.initials: MO
authors.lastname: Schemberger
authors.forename: Elisangela
authors.initials: E
authors.lastname: Bellafronte
authors.forename: Viviane
authors.initials: V
authors.lastname: Nogaroto
authors.forename: Mara Cristina
authors.initials: MC
authors.lastname: Almeida
authors.forename: Guilherme Schnell
authors.initials: GS
authors.lastname: Schühli
authors.forename: Roberto Ferreira
authors.initials: RF
authors.lastname: Artoni
authors.forename: Orlando
authors.initials: O
authors.lastname: Moreira-Filho
authors.forename: Marcelo Ricardo
authors.initials: MR
authors.lastname: Vicari
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry; D005260:Female; D005399:Fishes / Q000145:classification / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D008297:Male; D010802:Phylogeny; D012091:Repetitive Sequences, Nucleic Acid; D012730:Sex Chromosomes
chemical_list: D004247:DNA