Ribosomal DNA and morphological analysis of Dactylogyrus species from freshwater fishes of India.

Dactylogyrus species (Dactylogyrideae: Monogenea) are a group of monogenean gill parasites these parasites are highly host specific to freshwater fish of family Cyprinidae. A method is presented for the isolation and morphometric analysis of hamuli marginal hooks and bars form individual dactylogrids monogenoidea using phase contrast microcopy and camera lucida drawing, while simultaneously processing for rDNA analysis using the polymerase chain reaction. The identification and taxonomy of the worms in question was done by the morphometrical methods and rDNA analysis. ITS-1 regions of the rDNA gene of worms were amplified, sequenced and then the discrimination was recorded at the species level. The studied segments were compared with the published data on such segments of other Dactylogyrids species and were found to have significant relationship in the genes and spacer regions of the rDNA.