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

Abstract

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 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 th chromosome pair of all populations. Nevertheless, in the specimens from the Paraná and São Francisco Basins the 5S rDNA clusters were interstitially located by FISH on the long arm of the 2 nd chromosome pair, while in the specimens from the Tocantins-Araguaia Basin these sites were observed on the long arm of the 9 th chromosome pair and on the short arm of the 17 th chromosome pair. These data suggest that the species currently named Leporellus vittatus may comprise a complex of cryptic species.

Chromosomal and morphological divergences in Atlantic populations of the frillfin goby Bathygobius soporator (Gobiidae, Perciformes)

“…Cytogenetic studies in fish populations have increasingly used mapping of 5S rDNA sites, both for evolutionary analyses (Martins and Galetti, 2001) and as cyto-population markers (Aguilar and Galetti, 2008). These sites are generally present in different chromosomes from those carrying the 45S genes, a pattern commonly found in vertebrates (Lucchini et al, 1993;Suzuki et al, 1996).…”

Mapping of Ribosomal DNA by FISH, EcoRI Digestion and Replication Bands in the Cardinalfish Apogon americanus (Perciformes)

“…The mapping of 5S rRNA genes has been used to identify both structural chromosome alterations as well as Rb translocations (Molina and Galetti 2002), besides numerical alterations related to different ploidy levels (Zhu et al 2006), or else populational differences (Aguilar and Galetti 2008). The lack of synteny between 18S and 5S rDNA subunits, as detected in A. americanus, represents the most frequent condition reported in fish species (Martins 2007), including several Perciformes groups, thus reinforcing the hypothesis of independent evolution between both gene families.…”

Karyoevolutionary aspects of Atlantic hogfishes (Labridae–Bodianinae), with evidence of an atypical decondensed argentophilic heterochromatin

“…; Molina and Galetti, 2002;Aguilar and Galetti, 2008;Motta-Neto et al, 2011a, b). B. rufus, B. pulchellus and B. insularis exhibited evolutionary conservativeness with respect to distribution of 18S rDNA sequences in chromosomes, in line with results obtained by Ag-NORs.…”