GENETIC STRUCTURES OF CHYDORUS SPHAERICUS POPULATIONS FROM LAKE DONGHU, WUHAN

To estimate the possible influence of the artificial embankments on the genetic structure of Chydorus sphaericus in Lake Donghu, the COⅠgene of C. sphaericus from Lake Donghu, Wuhan, was analyzed with classical DNA sequencing. The results showed that C. sphaericus collected from seven sampling sites at Lake Donghu were not classified into different groups. Both global test and pairwise difference test indicated that there was no remarkable inheritance difference among seven C. sphaericus populations. The N-J tree indicated that COⅠgene of C. sphaericus from Lake Donghu was clustered into one group and those from different regions were clustered into different groups except Lake Kookatsoon, Yukon Territory, which were clustered into the Lake Donghu group. The correlation analysis between pairwise distances of COⅠgene sequences of C. sphaericus and geography distances among sampling sites showed that there were distance-decay relationships regardless within Lake Donghu or in larger scales. This result indicated that there was distribution restriction in C. sphaericus populations. In conclusion, the artificial embankments in Lake Donghu that were built 50 years ago did not cause remarkable influence on the genetic structure of C. sphaericus population in Lake Donghu. The relatively strong passive diffusivity of C. sphaericus in small scales may be one of the reasons that neutralized the influence of the artificial embankments on the population genetic structure.