Population data and forensic efficiency of 21 autosomal STR loci included in AGCU EX22 amplification system in the Wanzhou Han population

Autosomal short tandem repeats (STRs), widely distributed in the whole human genome, play an important role in personal identification and parentage testing. In this study, the allele frequencies and forensic efficiency parameters of 21 autosomal STR loci included in the AGCU EX22 kit were obtained from 433 Chinese Han individuals residing in the Wanzhou District in the north of Chongqing Municipality, Southwest China. No deviation from Hardy-Weinberg equilibrium was observed in all of the 21 STR loci. A total of 241 alleles were observed with allele frequencies ranging from 0.0011 to 0.5418. The cumulative power of discrimination and the cumulative probability of exclusion were 0.9999999999999999999999999 and 0.999999996, respectively. The results of genetic distance, neighbor-joining tree, principal component plots, and multidimensional scaling analysis revealed that the Wanzhou Han had more genetic differences when compared with Kazakh and Uyghur populations from Xinjiang than other included reference populations. In summary, the results in forensic characteristic analyses indicated that the 21 STRs are highly polymorphic and can be served as a useful tool in forensic routine practices. The population comparison indicated that close geographic or ethnic origin groups had a strong genetic affinity with each other.