RESUMO
Objective To investigate the genetic data of the 19 X-STR loci in three ethnicities of China ( Han, Gelao,Miao) and to evaluate the application in forensic science.Methods The DNA samples of unrelated individ-ual in Han (n=308), Gelao (n=398), Miao (n=323) ethnicities were amplified using MicroreaderTM19X ID System kit, and the PCR products were analyzed by electrophoresis through 3500XL genetic analyzer. The fragment sizes of alleles were taken subsequently by GeneMapper? ID-X. Allele frequencies and national genetics parameters of the 19 X-STR were analyzed by statistics. The allele frequencies were compared among the three nationalities and were compared with available data of other Han ethnicities from different regions. Results After the Bonferroni correction at a 95% significance level, no significant departures from the Hardy-Weinberg equilibrium was observed. Linkage disequilibrium test showed no significant allelic association between all 19 X-STR loci after Bonferroni’s correction. The cumulative discrimination power in females and in males were greater than 0.999 999 999 99 and 0.999 999 999 94,respectively. The combined power of exclusion in trios and in duos were greater than 0.999 999 999 36 and 0.999 999 52,respectively. The p values,calculated throuth Arle-quin v3.5 software,there were significantly different as detected at loci of X-STR among the different nationalities. Conclusions This panel of X-STR is highly polymorphic in China’s three ethnicities and can be served as a supple-mentary to the current STR system for individual identification.