Chromosome mapping of 5S rRNA genes differentiates Brazilian populations of Leporellus vittatus (Anostomidae, Characiformes)

• Published in: Genetics and molecular biology 2008, Vol.31 (1 suppl), p.188-194
• Main Authors: Aguilar, Cecilia Teixeira de, Galetti Junior, Pedro Manoel
• Format: Article
• Language: English
• Subjects: 45S rDNA; 5S rDNA; Anostomidae; BIOCHEMISTRY & MOLECULAR BIOLOGY; C-bands; Characiformes; GENETICS & HEREDITY; karyotype
• ISSN: 1415-4757; 1678-4685; 1415-4757; 1678-4685
• DOI: 10.1590/S1415-47572008000200004

Among the anostomid fishes, the genus Leporellus is represented by only three species: L. nattereri, endemic of the Amazon River, L. retropinnis, endemic of the Piracicaba River, and L. vittatus, widely distributed in rivers from Peru, Colombia, Guianas, and different major hydrographic basins of Brazil. A cytogenetic study carried out on specimens of Leporellus vittatus from three major Brazilian hydrographic basins evidenced a karyotype of 54 metacentric and submetacentric chromosomes. C- banding analysis revealed the presence of large pericentromeric heterochromatic segments in all chromosomes and a telomeric block coincident with the NOR sites. Ag, CMA sub(3) or MM staining, and FISH with ribosomal probes located the 45S ribosomal genes on the terminal region of the long arm of the 12 super(th) chromosome pair of all populations. Nevertheless, in the specimens from the Parana and Sao Francisco Basins the 5S rDNA clusters were interstitially located by FISH on the long arm of the 2 super(nd) chromosome pair, while in the specimens from the Tocantins-Araguaia Basin these sites were observed on the long arm of the 9 super(th) chromosome pair and on the short arm of the 17 super(th) chromosome pair. These data suggest that the species currently named Leporellus vittatus may comprise a complex of cryptic species.