Standardization of Amplification Conditions for 5S rDNA Technique to Obtain Species Specific Molecular Markers in Hypostomus Populations from the Ivaí River

Abstract

Fish are the most diverse vertebrates, with nearly 20,000 described species. Although freshwater fish make up between 20 and 25% of vertebrate biodiversity, between 30 and 40% of all the diversity in neotropical ichthyofauna has not been described. Since the family Loricariidae, particularly the genus Hypostomus, comprises great morphological similarity between the specimens, their identification and the establishment of phylogenetic relationships among species are complex. There is no taxonomic consensus on more than 16 species of Hypostomus in the Paraná river basin, including the Ivaí river. Molecular markers techniques, especially 5S rDNA, have been used in the identification of neotropical fish species. Current study standardizes optimal conditions for the amplification of 5S rDNA technique to obtain molecular markers that may be used to identify Hypostomus specimens. The amplification of DNA fragments from Hypostomus by 5S rDNA, using DNA in a concentration of 5ng and denaturing temperatures of 92°C, annealing at 40° C and extension at 72°C was achieved. Results show that the above technique may be used in future studies on genetic variability of this species using molecular markers.