Forensic insights and genetic diversity: unveiling the Yunnan Yi and Qinghai Tibetan groups in China using a Multi-InDel panel

Aim: Multi-InDel markers, which exhibit greater genetic diversity than single InDel loci, hold significant potential for forensic applications. To enhance the detection rate in degraded DNA samples, our laboratory developed a novel Multi-InDel panel comprising 41 Multi-InDel markers. This study aims to verify the forensic efficacy of this Multi-InDel panel in two Chinese minority groups. Methods: In this study, we assessed the forensic performance of this Multi-InDel panel by genotyping 92 Yunnan Yi (YNY) and 173 Qinghai Tibetan (QHT) individuals, both belonging to Chinese ethnic minorities. We also explored the genetic relationships between these two groups and 28 global reference populations. Results: The results showed that 40 of the Multi-InDel markers (excluding MI38) exhibited high polymorphism in the YNY and QHT groups, with cumulative probabilities of matching of 2.28 × 10-26 (YNY) and 5.64 × 10-26 (QHT), and cumulative probabilities of exclusion of 0.9999995429 (YNY) and 0.9999984549 (QHT), respectively. Full sibling identification accuracies in the YNY and QHT groups, along with seven East Asian reference populations, averaged 98.89%, 96.48%, 90.47%, 78.82%, and 61.83% at likelihood ratio (LR) thresholds of 1, 10, 100, 1,000, and 10,000, respectively. Genetic analyses revealed close affinities between the studied groups and other East Asian populations. Additionally, the Multi-InDel panel effectively distinguished African, East Asian, and European populations. Conclusion: The Multi-InDel panel demonstrated strong performance in various forensic applications, including individual identification, paternity testing, and full sibling identification in the YNY and QHT groups. Moreover, these two groups exhibited closer genetic relationships with East Asian populations than with other global populations.