Obtaining 5S rDNA molecular markers for native and invasive Cichla populations (Perciformes - Cichlidae), in Brazil

Abstract

The 5S rDNA gene is informative and has high conservation rates along the eukaryotic genome, having unique hereditary characteristics. Molecular studies with the 5S rDNA gene have been carried out with several groups, including some species of fish, aiming at solving phylogenetic relationship problems, ancestral patterns and genetic diversity among groups in natural populations. Species of the Cichla genus, introduced in the upper Paraná river basin, present some genetic polymorphisms detected by RAPD and SPAR analyses. These species have been intercrossing and forming viable hybrids, with greater genetic variability. The objective of this work was to standardize the amplification methodology for the non-transcribed regions of 5S rDNA multigenic family of Cichla, and to obtain specific markers for parent species that could also be identified in the hybrids. Sixty-five specimens of Cichla collected from the upper Paraná river and Amazon basins were analyzed. Although molecular markers that could be useful in the identification of hybrids were not obtained, genetic molecular 5S rDNA species-specific markers for Cichla temensis that can be employed to identify of this species, as well population markers that can be useful in population genetic variability studies, were obtained.