title: Isolation and characterization of 5S rDNA sequences in catfishes genome (Heptapteridae and Pseudopimelodidae): perspectives for rDNA studies in fish by C0t method.
abstract: Sequences of 5S ribosomal RNA (rRNA) are extensively used in fish cytogenomic studies, once they have a flexible organization at the chromosomal level, showing inter- and intra-specific variation in number and position in karyotypes. Sequences from the genome of Imparfinis schubarti (Heptapteridae) were isolated, aiming to understand the organization of 5S rDNA families in the fish genome. The isolation of 5S rDNA from the genome of I. schubarti was carried out by reassociation kinetics (C0t) and PCR amplification. The obtained sequences were cloned for the construction of a micro-library. The obtained clones were sequenced and hybridized in I. schubarti and Microglanis cottoides (Pseudopimelodidae) for chromosome mapping. An analysis of the sequence alignments with other fish groups was accomplished. Both methods were effective when using 5S rDNA for hybridization in I. schubarti genome. However, the C0t method enabled the use of a complete 5S rRNA gene, which was also successful in the hybridization of M. cottoides. Nevertheless, this gene was obtained only partially by PCR. The hybridization results and sequence analyses showed that intact 5S regions are more appropriate for the probe operation, due to conserved structure and motifs. This study contributes to a better understanding of the organization of multigene families in catfish's genomes.
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil.
authors.forename: Juceli Gonzalez
authors.initials: JG
authors.lastname: Gouveia
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil.
authors.forename: Ivan Rodrigo
authors.initials: IR
authors.lastname: Wolf
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil.
authors.forename: Vivian Patrícia Oliveira
authors.initials: VP
authors.lastname: de Moraes-Manécolo
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil.
authors.forename: Vanessa Belline
authors.initials: VB
authors.lastname: Bardella
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil.
authors.forename: Lara Munique
authors.initials: LM
authors.lastname: Ferracin
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil.
authors.forename: Lucia
authors.initials: L
authors.lastname: Giuliano-Caetano
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: da Rosa
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, CCB, Universidade Estadual de Londrina, P.O Box 6001, Londrina, Paraná, CEP 86051-970, Brazil. anadias@uel.br.
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: Dias
keywords: C0t; Genomics micro-library; Hybridization; Pisces