title: Molecular characterization and physical mapping of two classes of 5S rDNA in the genomes of Gymnotus sylvius and G. inaequilabiatus (Gymnotiformes, Gymnotidae).
abstract: The nucleotide sequences of the 5S rRNA multigene family and their distribution across the karyotypes in 2 species of Gymnotiformes, genus Gymnotus (G. sylvius and G. inaequilabiatus) were investigated by means of fluorescence in situ hybridization (FISH). The results showed the existence of 2 distinct classes of 5S rDNA sequences in both species: class I and class II. A high conservative pattern of the codifying region of the 5S rRNA gene was identified, contrasting with significant alterations detected in the nontranscribed spacer (NTS). The presence of TATA-like sequences along the NTS of both species was an expected occurrence, since such sequences have been associated with the regulation of the gene expression. FISH using 5S rDNA class I and class II probes revealed that both gene classes were collocated in the same chromosome pair in the genome of G. sylvius, while in that of G. inaequilabiatus, class II appeared more disperse than class I.
authors.affiliation: Instituto de Biociências de Botucatu, Departamento de Morfologia, Universidade Estadual Paulista, São Paulo, Brazil. pcardim@ibb.unesp.br
authors.forename: P C
authors.initials: PC
authors.lastname: Scacchetti
authors.forename: J C P
authors.initials: JC
authors.lastname: Alves
authors.forename: R
authors.initials: R
authors.lastname: Utsunomia
authors.forename: F L
authors.initials: FL
authors.lastname: Claro
authors.forename: L F
authors.initials: LF
authors.lastname: de Almeida Toledo
authors.forename: C
authors.initials: C
authors.lastname: Oliveira
authors.forename: F
authors.initials: F
authors.lastname: Foresti
mesh_terms: D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping / Q000379:methods*; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004587:Electrophoresis, Agar Gel; D016678:Genome / Q000235:genetics*; D023702:Gymnotiformes / Q000145:classification / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D007621:Karyotyping; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal; D012341:RNA, Ribosomal, 5S