Population genetic data for 12 X-STR loci in the Northern Han Chinese and StatsX package as tools for population statistics on X-STR

The X-chromosomal short tandem repeat (X-STR) has the advantage in female traces identification against male contamination and in complex kinship cases. In this study, a total of 516 Northern Han Chinese were genotyped using the Investigator® Argus X-12 QS Kit and pairwise genetic distances (FST) were measured between Northern Han Chinese and 35 published populations using the same 12 X-STR loci in four presumed linkage groups (LG). Meanwhile, the StatsX package was compiled to aid the analysis of population statistics on X-STR. Off-ladder alleles were investigated by Sanger sequencing or next generation sequencing (NGS). The results showed that high combined PDM, PDF, MECKrüger, MECKishida, MECDesmarais and MECDesmarais Duo based on allele frequencies were achieved as 0.999999998, >0.999999999, 0.999996425, 0.999999993, 0.999999993 and 0.999998732, respectively, so did they based on haplotype frequencies. Averaged FST and multidimensional scaling (MDS) plot generally mirrored with the biogeography distribution of the studied populations and their historical relationships. A total of 16 unique off-ladder alleles were observed in this experiment, four of which have not been reported yet. The StatsX package could obtain full concordance with established software. Overall, the Investigator® Argus X-12 QS Kit may provide high polymorphic information for forensic identification and kinship analysis in the Northern Han Chinese population, and the StatsX package can make the workflow smoother for researchers to do population statistical analysis on X-STR.