Polymorphism of internal transcribed spacer 2 [ITS-2] sequences and genetic relationships between Fasciola hepatica and F.gigantica

Nucleotide sequences of internal transcribed spacer 2 (ITS-2) of nuclear DNA were obtained from 58 adult worms Fasciola hepatica and F. gigantica of naturally infected cattle and sheep in Russia, Ukraine, Belarus, Armenia, Uzbekistan, Turkmenistan and Tajikistan. No variation was observed between 43 liver flukes F. hepatica from Russia, Belarus, Ukraine, Armenia and Turkmenistan. Only one specimen from Armenia had a single unique transversion C-G (0.3% variation). F. gigantica from Turkmenistan, Tajikistan and Uzbekistan differed at four nucleotide transitions (1.1% variations). For comparative purpose, the ITS-2 sequences of two species from Europe, Africa, Asia, America, Australia and Oceania were used and evolution history of ITS-2 sequences of Fasciola species was reconstructed with statistical parsimony network (SPN) method. The relationships between F. hepatica and F. gigantica from different regions were discussed.