GENETIC-VARIATION IN GEOGRAPHICALLY ISOLATED POPULATIONS AND SUBSPECIES OF ONCOMELANIA-HUPENSIS DETERMINED BY A PCR-BASED RFLP METHOD

Previously, the species complex Oncomelania hupensis, individuals of w hich act as intermediate hosts for the human bloodfluke Schistosoma ja ponicum, has been characterised by morphological and isoenzyme criteri a. We have examined genetic variation between and within three subspec ies of Oncomelania hupensis, i.e. O. h. hupensis (China), O. h. quadra si (Philippines) and O. h. nosophora (Japan), by direct means using a PCR-based RFLP method. The subspecies of O. hupensis were readily dist inguished by their characteristic restriction patterns, supporting iso enzyme data which suggests these may warrant species-specific status. No genetic variation was observed between O. h. quadrasi from differen t islands within the Philippines. In contrast, geographical isolates o f O. h. hupensis differed markedly by this method indicating several g enetically distinct populations of O. h. hupensis occur in China.