Genetic polymorphisms and application of 9 STR loci of 5 ethnic groups in Gansu and Qinghai

Objective: To examine the genetic polymorphism of 9 STR loci in 5 ethnic groups (including Tu, Sala, Dongxiang, Baoan and Yugu) in Gansu and Qinghai, and to evaluate its application. Methods: Nine STR loci (D3S1358, FGA, TH01, D7S820, VWA, CSF1P0, D5S818, D13S317 and TPOX) were selected as genetic markers. With STR compound amplification and genescan methods, in which STR loci were marked by fluorescence, the genotype of 5 ethnic groups were examined in 606 unrelated individuals by ABI 377 sequencer. These parameters, such as polymorphism information content (PIC), heterozygosity (H), discrimination power (DP) and probability of paternity exclusion (PPE) were calculated. Results: The genotype frequencies of the 9 STR loci were in accordance with Hardy - Weinberg equilibrium. PIC was within 0.6054-0.8735, H was within 0.6158-0.8736, DP was within 0.7964-0.9691, and PPE was within 0.4610-0.8838. Cluster analysis based on allele frequencies in genesis showed Tu, Sala, Dongxiang and Baoan ethnic groups were very close, but Yugu was a little bit far. There were obvious gene exchanges among the populations in north and south of China. Conclusion: All the 9 STR loci are highly polymorphic in the 5 ethnic groups, which can be useful genetic markers in forensic medicine and population genetics.