Genetic polymorphism and phylogenetic analyses of 21 non-CODIS STR loci in a Chinese Han population from Shanghai

Background Short tandem repeats (STRs) are essential genetic markers for forensic applications and population estimations; thus the population genetics of STR loci have been extensively studied and discussed. Methods In the present study, we detected 21 autosomal noncombined DNA index system (non-CODIS) STR loci in a Chinese Han population from Shanghai, calculated their forensic parameters and analyzed their genetic relationships with reported reference populations in mainland China. Results A total of 173 alleles were observed, with corresponding allele frequencies from 0.0020 to 0.5512. The cumulative power of discrimination (CPD) and the cumulative probability of exclusion (CPE) values of the 21 STR loci were 0.999999999999999999997337058271 and 0.99999953732495, respectively. The results of interpopulation differentiation, phylogenetic, multidimensional scaling, and structure analyses indicated a closer genetic relationship of the studied population with Han populations from other regions of China than with other populations. Conclusions The 21 STR loci exhibited high genetic polymorphism in the studied Shanghai_Han population and could be used for forensic applications and population genetic studies.