Abstract: By using eight highly polymorphic microsatellite DNA loci, this paper analyzed the genetic structure of wild Macrobrachium nipponense populations
in Taihu Lake. For the 15 M. nipponense populations in the Lake, there were at least three of the loci presenting heterozygosity deficiency and obvious deviation from Hardy-Weinberg equilibrium after Bonferroni correction. The observed heterozygosity values of the 15 populations were all above 0.683, displaying a high genetic diversity, but the diversity varied obviously with site. For example, the genetic diversity of the eastern and southern populations at Dukou and Luxiang was higher than that of the western and northern populations at Huazhuang and Yangzhu. For the 15 populations, parts of the loci showed heterozygote excess and departure from mutation-drift equilibrium, suggesting that the population structure had experienced bottleneck effect and the population amount had declined. The AMOVA analysis across all the populations and loci showed that the genetic divergence among the 15 populations was at a lower level (F_ST=0.011). 98.9% of the genetic variation came from intra-population, and 1.1% came from inter-population, suggesting that all the M. nipponense populations in the Lake could be protected and managed as a single unit in genetic resource. However, the genetic distance between Huazhuang and Wutangmen populations reached 0.206, being close to the delimitation of species identification. Further studies would be needed for the sustainable utilization of the genetic resource of M. nipponense in Taihu Lake.

Key words: Macrobrachium nipponense, Taihu Lake, microsatellite, genetic structure, Fengqiu County, the lower reaches of the Yellow River., amphibian, agricultural landscape