| Thousand-island Lake is a typical fragmentation landscape cause of dam built which abound land-bridge islands. The diversity of the insect population distribute in the islands of Thousand-Islands Lake will be changed with habitat destroying and isolation aggravating. In this research, We collect insect species Loxoblemmus aomoriensis Shiraki in the July and August of 2015 to study its genetic diversity and genetic structure,the result reveal : There are 18 haplotypes have been defined within 10 population based on mitochondrial DNA gene COI fragment. All the population show high genetic diversity, the haplotypes among 0.7636 and 0.945. The regression analyses shows that islands area have significant correlation with genetic diversity,P-value<0.001 and R2=0.5094,while other island attribute don’t show any correlation whit genetic diversity. The Tajima’s D neutrality tests in 10 population shows that most population have experienced a population expansion recently cause of the value is negative. We calculated genetic differentiation between each population, the pairwise Gst values range from-0.05873 to 0.29588, 28.9% pairwise value greater than 0.05 and less than 0.15,that means 28.9% show medium genetic differentiation;About 71.1% pairwise value greater than 0 and less than 0.05,that means 71.1% show none genetic differentiation. The pairwise gene flow value range from 1.8034 to 43.24453; about 53.3% Nm value greater than 4 and 46.7% pairwise Nm less than 4 and greater than 1,there is not any value less than 1. The mantel test reveal that both genetic differentiation and gene flow have shown the significant correlation with geography distance,genetic differentiation and gene flow conform to IBD model and stepping-stone model. Spatial analysis of molecular variance reveal 10 population show significant regional in grouping, the population shows more genetic similarity in the comparability area. |
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