Characterization of internal transcribed spacer (ITS-1) ribosomal DNA sequence of Fasciola gigantica

Fasciola gigantica flukes were collected from Bareilly and Internal Transcribed Spacer-1 (ITS1) of ribosomal DNA from these was characterized. The ITS-1 was amplified by Polymerase Chain Reaction (PCR), and the amplified PCR product was ligated with pGEM-T Easy plasmid cloning vector and transformed into DH5á strain of E. coli. Sequencing of recombinant clone revealed that the length of the ITS-1 was 433 bp comprising 422 bp of complete ITS-1 gene. While comparing with published ITS-1 sequences of F. gigantica isolates from China and Meghalaya, 98.8% homology was observed with differences at only 5 positions. On the basis of sequence analysis, it was found that restriction enzyme RsaI could be used for strain variation studies by restriction fragment length polymorphism (RFLP) analysis. Published sequences of ITS-1 of Chinese and Meghalayan strains were 100% homologous. The present study could be helpful in molecular taxonomic identification of Fasciola species.