Short Tandem Repeats (STRs) are the gold standard for human identification. They are widely used in crime scene investigations, kinship testing, and disaster victim identification due to their high polymorphism, sensitivity, and discrimination power. Combining autosomal STRs and sex-specific STRs (Y-STRs and X-STRs) across multiple tissues yields highly informative genetic profiles. Y-STRs, which target Y-chromosome DNA inherited through the paternal line, are particularly useful when autosomal STR profiling is inconclusive. They enhance the reliability of the results in establishing patrilineal relationships of male offspring, paternal kinship testing, and missing persons and disaster victim identification, as well as in sexual assault cases when male DNA is masked by female DNA. In complex mixtures involving male victims or multiple male contributors, autosomal DNA profiling is challenging. Even with advanced probabilistic genotyping software, separating these mixtures can still be limited due to issues like template imbalance, low quantity DNA, or degraded DNA. In such cases, Y-STR analysis serves as a valuable complementary tool. However, Y-STRs cannot distinguish between closely related males within the same paternal lineage, limiting their individualising power. Their evidentiary value also depends on robust population-specific databases for accurate statistical interpretation. This review outlines the practical uses and limitations of Y-STR analysis, emphasising the importance of population databases such as the Y Chromosome Haplotype Reference Database in evaluating evidentiary weight. Based on these considerations, this study highlights the effectiveness of the PowerPlex® Y23 system, as a valuable complementary tool to autosomal STRs, particularly in challenging cases where autosomal results alone are insufficient.
Rathnayake et al. (Mon,) studied this question.