Elucidation of genetic variability among different isolates of Fasciola gigantica (giant liver fluke) using random-amplified polymorphic DNA polymerase chain reaction.

The present communication focuses on molecular characterization of Fasciola gigantica isolates derived from cattle, buffalo, and goat using random-amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) analysis to elucidate genetic variability between the three isolates. Seventeen random oligonucleotide primers of 10-11 bases with GC content varying from 50-81.8% were used in the study. Depending upon the F. gigantica isolate-primer combination, one to five fragments in the range of 327-1,973 bp were amplified. It was significant to observe that, out of the 17 primers directing amplification of DNA fingerprints, only two designated as AP9 and AP14 were found to be of potential interest in the generation of polymorphic DNA. On the basis of similarity coefficient data, it may be suggested that cattle and buffalo isolates of F. gigantica show 100% homogeneity against 92.68% similarity coefficient observed between goat and cattle/buffalo isolates. In other words, 7.32% divergence was observed between goat and cattle/buffalo isolates while the primers AP1, AP4, AP10, AP13, and AP17 were able to generate monomorphic DNA fingerprints. Primers AP9 and AP14 are potentially informative in terms of the polymorphic nature of the fingerprints generated in RAPD assays. The finding of the absence of 626-bp DNA fragment in the goat and the uniqueness of the AP14 in generating a single RAPD-PCR product of 1,211 bp as against the product size of 1,162 bp in cattle/buffalo seem to be significant. This is the first report of elucidation of RAPD-PCR based molecular variability in the DNA fingerprinting pattern of F. gigantica isolated from cattle, buffalo, and goat.