RAPD analysis is used to assay the population genetic structure and genetic differentiation of pufferfish T. rubripes and T. pseudammus. One hundred and twenty fragments are amplified with 21 random sequence 10-mer primers. The proportion of polymorphic fragments of T. rubripes populations from the coast of China (TRC), the coast of Japan (TRJ), general population of T. rubripes both from China and Japan (TRCJ), and the population of T. pseudommus are 31.7%, 33.3%, 35.0% and 39.2 % respectively. The mean expected heterozygositiee of the four populations are 0. 116, 0. 125, 0. 126, and 0. 144, respectively. Low genetic distances (ranging from 0.0118 to 0.0309) and Fst estimates (0.020 to 0.024) among the populations in-dicated that there is no significant differentiation between T. rubripes and T. pseudommus and suggested that only one species is involved.
