We analyzed restriction fragment length polymorphisms (RFLPs) at the D-loop region of mitochondrial DNA (mtDNA) in endangered cyprinid subspecies Pseudorasbora pumila subsp. sensu Nakamura (1963). All the six population samples consisted of three wild populations and three artificial breeding populations from Aichi and Gifu Prefectures. The examination showed marked monomorphism and three genotypes were distributed along with each geographical locations. As a result, some possibility was shown that the parents of artificially breeding populations had been monomorphic when they were collected.
We thought experimental tests should be done for the conservation of this subspecies, stocking three genotypes under various conditions and investigating their adaptability.