Correlation between sample size and Obolodiplosis robiniae genetic diversity index based on microsatellite DNA data.
Objective: To obtain proper sample size for determining the genetic structure of a population of black locust gall midge Obolodiplosis robiniae (Haldemann) (Diptera, Cecidomyiidae). Method: The sample sizes with 12 gradients and 11 polymorphic microsatellite loci were used to assess five O. robiniae populations. Result: The results revealed that the sample size took significantly positive correlation with the number of alleles per locus (Na), and moderately positive correlation with the effective number of alleles per locus (Ne), but had moderately negative correlation with observed heterozygosity, however little influence was found on the expected heterozygosity, Neis genetic diversity and polymorphism information content. When the sample size <25, the number of alleles per locus increased rapidly and observed heterozygosity greatly changed, but they changed gently when the sample size >30. Conclusion: Concerning the genetic diversity analysis for populations of O. robiniae with microsatellite DNA markers, the optimum sample size appears to be 25-30, and the optimum parameters are the expected heterozygosity, Nei's genetic diversity and polymorphism information content. The results of this study are helpful to microsatellite marker-based analyses of the genetic structure of populations of other invasive dipteran pests.