Forensic features and phylogenetic analyses of Sichuan Han population via 23 autosomal STR loci included in the Huaxia Platinum System

Short tandem repeats (STRs) are DNA regions with a variable number of repeated units (2–6 bp) and attractive to genetic application like forensic, population genetics, and anthropological studies. The Huaxia Platinum System allows the multiplex amplification of 23 autosomal STR loci and two gender determination loci. In the present study, genetic polymorphisms of these 23 autosomal STR loci were first obtained from 309 Sichuan Han individuals, southwest China. No evidence of deviation from the Hardy-Weinberg equilibrium (HWE) was identified. The combined match probability (CMP), combined power of discrimination (CPD), and combined power of exclusion (CPE) are 1.087 × 10⁻²⁷, 0.999999999999999999999999999, and 0.9999999996 in the Sichuan Han Chinese population, respectively. The inter-population differentiation, PCA, MDS, and phylogenetic analysis revealed that Sichuan Han had a closer genetic relationship with neighboring Han Chinese populations. Our findings indicated that the 23 autosomal STR loci are polymorphic and informative in studied southwestern Chinese Han population and can be utilized as a powerful tool for forensic applications. In addition, population comparisons demonstrated that the genetic similarities widely existed among Han Chinese populations distributed in different administrative divisions, and genetic differences had existed between minorities (most prominently for Uyghur and Kazakh) and Han groups.