[Genetic Variation of Oncomelania hupensis in Weishan Lake of Shandong Province Using Microsatellite DNA Markers].

Objective: To identify the genetic variation of Oncomelania hupensis between Weishan Lake population and Yangtze River population.

Methods: O. hupensis snails were collected from Jiangdu District of Yangzhou City, Yizheng City, Danyang City, and Liuhe District of Nanjing City in Jiangsu Province, as well as Weishan Lake of Jining City in Shandong Province. Four polymorphic microsatellite DNA loci（A18, C22, T4-33 and T6-17） were amplified by using microsatellite PCR to analyze the number of alleles （Na）, the expected heterozygosity （He）, the observed heterozygosity （Ho） and the average number of pairwise differences between populations. Analyses of molecular variance (AMOVA) and cluster analysis were performed to find the genetic variation between O. hupensis snail populations. Unweighted pair group method with arithmetic mean （UPGMA） and neighbour joining (NJ) method were used to construct the phylogenetic tree to describe genetic variation and clustering among populations. Mantel test was carried out to detect the correlation between the genetic distance and geographical distance.

Results: A total of 103 snails were collected. The snail populations of Jiangdu, Yizheng, Danyang, Liuhe, and Weishan Lake had Na of 7.50, 12.50, 10.00, 11.50; Ho of 0.16, 0.27, 0.17, 0.30, 0.22; and He of 0.81, 0.91, 0.84, 0.90, 0.92, respectively. The Weishan Lake population showed relatively higher levels of the three indicators, indicating a higher genetic diversity, but with no significant difference with the other four populations. The average number of pairwise differences was lowest between the Weishan Lake and Jiangdu populations（0.79）, and it was higher between Danyang population and the others（0.87-0.97）. AMOVA result showed the inter-individual genetic variation accounted for 92.50% of the total variations. NJ and UPGMA analysis showed Jiangdu and Weishan Lake populations gathered together in one branch, Yizheng and Liuhe populations formed another relatively independent branch, and then was Danyang population. Genetic distance and geographical distance showed no correlation by Mantel test.

Conclusion: There is a high genetic diversity of O. hupensis in Weishan Lake and Yangtze River populations, and no significant genetic divergence between Weishan Lake snail population and its original Yangtze River population.