Shanxi Han X-str Loci Dxs9902, Dxs7132 Genetic Polymorphism And Forensic Applications

Objective To provide the evidence for the application of DXS9902 and DXS7132 in forensic science and population genetics by investigating their allele and haplotype frequencies of the two X-STR locus in the Han population lived in Shanxi province,and discuss the possibility of applying them to forensic casework.Methods EDTA-blood specimens were collected from 210 unrelated individuals (120 females, 90 males) in Shanxi Han population. Different tissues of one corpse were analyzed including blood, muscle, heart, liver and kidney et al. Sample of 15 family trios were investigate. All blood-specimens were anticoagulated with EDTA, the Genomic DNA was extracted by phenol-chloroform method and the two locus DXS9902 and DXS7132 were amplified with PCR. The PCR products were typed on 8% non-denaturing polyacrylamide gel electrophoresis followed by silver-staining. Allele frequencies, genotype frequencies and haplotype frequencies were obtained by a direct calculation; test of Hardy-Weinberg equilibrium for female genotype data, comparing of allele frequencies between male and female population, and comparing of genetic data between different populations were performed byχ~2 test; also genetic parameters were calculated.Results Among 120 female and 90 male unrelated individuals from ShanXi Han population, DXS9902 exhibited 6 alleles named 9~14 and their frequencies ranging from 0.0091～0.4182, DXS7132 detected 5 alleles named 12~16 and their frequencies ranging from 0.0758～0.3515, allele frequencies differentiation was not observed between male and female populations. Respectively, 17,15 genotypes of 2 X-STRs were detected in females,heterozigosity for females were 0.6833,0.7333. and both their genotype frequencies did not depart from Hardy-Weinberg equilibrium. Discrimination power for females of each locus were 0.8122, 0.9006, probability of exclusion were 0.4847,0.5498. Total 20 haplotype were identified in males, the gene diversity, discrimination power, and probability of exclusion were 0.9398, 0.8928 and 0.8006, respectively. The typing results of different tissues from one individual were identical. No mutations were found from 15 family trios.Conclusion These results indicate that the DXS9902 and DXS7132 locus are high genetic polymorphic, the haplotype diversity shows good discriminating power and high excluding chance of paternity. They are high valuable in the application of forensic Medicine and population genetics.