Chromosomal Characterization of Prochilodus lineatus from Paraná River, Corrientes, Argentina. I.

B Chromosomes and NOR Banding

Abstract

The fish of the genus Prochilodus, commonly known as sábalo, are of great economic and ecological importance. Different species of this genus are widely distributed throughout all the basins of South America. Cytogenetic analysis performed on specimens of Prochilodus lineatus from Puerto Abras (Paraná River, Argentina), revealed the occurrence of 54 chromosomes of meta-submetacentric type, together with the presence of small supernumerary chromosomes with intra and interindividual variations. The use of the 18S rDNA probe confirmed the results obtained with Ag-NORs, identifying the presence of a metacentric chromosome pair with ribosomal cistrons in interstitial position in the long arm. Through both of these techniques are noted differences in the size of the nucleolar regions, this variation is probably related to the occurrence of events of duplication and/or deletion.