Survey of mitochondrial DNA haplotypes of Potamopyrgus antipodarum (Caenogastropoda: Hydrobiidae) introduced into Japan

Potamopyrgus antipodarum from 13 locations in central and western Japan were investigated for mitochondrial DNA haplotypes. Two haplotypes (JA and JB) were found based on an analysis of a 343-bp sequence of the cytochrome c oxidase subunit I gene. The JB type comprised two subhaplotypes (JB-I and JB-II), which were distinguishable by an additional sequence of 289 bp. Eleven populations were likely monomorphic in the mtDNA haplotype, while two populations, which were supposed to have been established recently, were polymorphic, encompassing JA and JB haplotypes. This result suggests that different haplotypes invaded Japan via different routes and that polymorphic populations were formed by colonization from more than one source population.