Molecular characterization and phylogeny based on ITS2 and 28S regions of rDNA of Microphallus sp. (Digenea: Microphallidae) parasitic in freshwater crabs of Manipur, India

Abstract Freshwater crabs (Potamiscus manipuriensis), commonly consumed as local delicacies by the native people in the state of Manipur, were found to harbour metacercariae of Microphallus sp. (Family Microphyllidae), which were morphologically different from metacercariae of Microphallus indicus reported earlier from a different host (Barytelphusa lugubris mansoniana) in Meghalaya, another state in Northeast India. So, PCR-based molecular characterization of this metacercaria was done utilizing rDNA marker regions: larger subunit (LSU) or 28S and inter-transcribed spacer 2 (ITS2). Sequence and phylogenetic analyses confirmed that the taxon under study belonged to family Microphyllidae. The ITS2 secondary structure data analyses also confirmed the primary sequence analysis. The analysis also revealed sequence differences in one hundred and nineteen bases (with 38 transitions, 35 transversions and 46 indels) with regard to 28S, though ITS2 showed sequence differences in 25 bases (10 transitions, 7 transversions and 8 indels) between the present microphallid and M. indicus.