The first X-STR population study for the South African population

The utilisation of X-chromosome short tandem repeats (X-STRs) for DNA profiling has been demonstrated to be particularly useful in resolving distant familial relations and deficiency paternity testing. The implementation of X-STRs within a medico-legal context requires baseline frequency data for the general population to allow for appropriate statistical interpretations of results. This study aimed to generate the first X-STR data for the South African population using an optimised and internally validated Qiagen Investigator Argus X-12 QS workflow. Biological samples from 1016 South African individuals (593 males and 423 females) with either African, European, Indian/Asian or mixed ancestry were processed. Herein, allele and haplotype frequencies, as well as forensic and population parameters for the four major South African population groups are reported. Locus DXS10135 was the most informative across all four population groups. Similarly, linkage group 1 had the highest haplotype diversity. An MDS plot revealed that the population groups in South Africa cluster with other global populations of similar ancestry, rather than each other. Additionally, 75 off-ladder alleles were identified, of which 37 were novel. X-STR analyses for civil inheritance disputes and the identification of unknown individuals are now possible given these data.