Nucleotide sequence, genomic organization and chromosome localization of 5S rDNA in two species of Curimatidae (Teleostei, Characiformes)

Lessandra Viviane De Rosa Santos,Fausto Foresti,Cesar Martins,Adriane Pinto Wasko,Claudio Oliveira

doi:10.1590/s1415-47572006000200009

Lessandra Viviane De Rosa Santos, Fausto Foresti + Show 3 more

Open Access

https://doi.org/10.1590/s1415-47572006000200009

Copy DOI

Abstract

The 5S ribosomal DNA (5S rDNA) of higher eukaryotes is organized in repeat units of tandem arrays composed of a 5S rDNA coding region, conserved even among non-related taxa, and a variable non-transcribed spacer sequence (NTS). To contribute to knowledge on the organization and evolution of vertebrate 5S rDNA we used PCR, nucleotide sequencing, Southern blot hybridization and chromosome fluorescence in situ hybridization (FISH) to investigate 5S rDNA tandem repeats in the South American Curimatidae fish Steindachnerina insculpta and Cyphocharax modesta. 5S rDNA repeats of 180 base pairs (bp) from both species were PCR-generated and sequenced evidencing the shortest 5S rDNA monomer so far described in eukaryote species. Southern blotting revealed that both species contained two tandem 5S rDNA classes, the PCR amplified fragment composed of 180 bp monomers and a class of 1600 bp monomers not detected by PCR. Chromosome mapping of the 5S rDNA repeats identified a major locus in both species and a second minor locus only in C. modesta. The Southern blot and chromosome mapping data indicate the presence of different types of 5S rDNA tandem repeats in the Curimatidae genome.

Highlights

Studies of ribosomal RNA genes have gained prominence in a broad range of animals and plants, especially for the identification of species and specific populations, the study of evolutionary relationships and the characterization of genome structure
Polymerase chain reaction amplification of the 5S ribosomal DNA (5S rDNA) of Steindachnerina insculpta and Cyphocharax modesta generated a single band of approximately 200 bp on agarose gel electrophoresis
Sequencing analyses showed 5S rDNA arrays of 180 bp, and the alignment of the sequences enabled the identification of 118 bp of the 5S rRNA gene and the whole non-transcribed spacer sequence (NTS) with 62 bp (Figure 1)

Summary

Introduction

Studies of ribosomal RNA genes have gained prominence in a broad range of animals and plants, especially for the identification of species and specific populations, the study of evolutionary relationships and the characterization of genome structure. Variations in the 5S rDNA non-transcribed spacer have been detected in some Neotropical fish such as Leporinus (Martins and Galetti, 2001a) and Brycon (Wasko et al, 2001) species.

Results

Conclusion