In most Japanese populations of dojo loach (Misgurnus anguillicaudatus), gonochoristic diploids genetically diversified groups (A and B, further subdivided into B1 B2) are present, whereas unisexual clonal lineages inhabit certain localities in the Hokkaido Ishikawa Prefectures Japan. Through a series genetic studies including DNA markers, loaches were deemed to originate from hybridization eve...