Abstract:

Procambarus clarkii is an alien invasive crayfish species that occurs in the major river basins along the middle and lower reaches of the Yangtze River. To understand genetic diversity and population structure of the species in the region, we collected 182 individuals from nine sites in four regions in the Yangtze, Huaihe, and Xin'anjiang River basins in Anhui Province. Using nine pairs of microsatellite markers, we studied the genetic differentiation, genetic structure and genetic clustering pattern of these P. clarkii populations. The expected heterozygosity (H_E) was 0.78 while the observed heterozygosity (H_O) was 0.36. Of the nine populations, the highest expected heterozygosity (0.76) was in the Wangjiang population, and the lowest (0.56) was for the Feixi population. Using a Bottleneck Test, we found a significant signal of heterozygote deficiency, indicating a recent decline in these populations. Our studies also showed that there were high levels of gene flow among populations, and a significant correlation found between genetic distance and geographic distance (r = 0.33, P < 0.05). We detected evidence of a significant jump dispersal event between the Xin’anjiang and Chengdonghu populations, thus indicating that human-mediated dispersal has played an important role in the present genetic structure of Procambarus clarkii population.