GENETIC-VARIATION IN THE TRIPLOIDS OF JAPANESE FASCIOLA SPECIES, AND RELATIONSHIPS WITH OTHER SPECIES IN THE GENUS

Twelve enzymes (encoded by 14 loci) in liver flukes of Fasciola specie s originating from Japan (parthenogenetic triploids), Korea (parthenog enetic diploids), the United States of America (USA) and Australia (al l sexual diploids) were analysed using starch gel electrophoresis. Var iation in electrophoretic patterns between samples was detected at fiv e enzyme loci (Ak, Got, Gpi, 6-Pgd and Pgm-2). Japanese worms (31, of which six were established as uniparental laboratory strains), which r eproduce by parthenogenesis, exhibited three different isozyme pattern s. This indicates that triploidy has arisen more than once in Japanese flukes. Japanese Fasciola sp. can be separated into three types on mo rphological grounds. For the six laboratory strains of Japanese worms, the parental morphological type was known. Each of the three isozyme patterns observed was restricted to one morphological type. Most allel es detected in the Japanese triploids were also found in diploid worms from the other countries: the only alleles not represented elsewhere were four at the Got locus and two at the Pgm locus. Flukes from a lab oratory strain derived from a single Korean diploid worm resembled the Japanese worms in genotype more closely than did American (seven unip arental laboratory strains) or Australian (30 worms) specimens. Worms from the last two countries were closely related.