Unveiling the genetic landscape of high-altitude adaptive ethnic groups with polymorphic markers: Implications of comprehensive forensic appraisals and population genetic investigations

Background: Deletion/insertion polymorphisms (DIPs), a novel class of biomarker, have been widely utilized in forensic areas for individual identification, paternity tests, and ancestral origin inference due to its applicability to degraded samples and low mutation rates. Despite the availability of a well-established commercial kit, the Investigator® DIPplex kit (Qiagen), certain loci exhibit limited levels of polymorphisms in East Asian populations, particularly in Chinese populations. Objective: This dissertation seeks to undertake a comprehensive evaluation about the forensic efficiency of a self-developed multiplex amplification system in high-altitude adaptive ethnic groups of China. Healthy unrelated Tibetan individuals residing in Tibet Autonomous Region and Qinghai Province were genotyped using previously reported 43 deletion/insertion polymorphism loci. Forensic statistical analyses including allele frequencies and forensic parameters were conducted in the two Tibetan groups, and the genetic relatedness of the studied groups with reference populations from the 1000 Genomes Project Phase 3 were investigated. Results: Forensic statistical results showed that the polymorphism information content values of the 43 deletion/insertion polymorphism loci in the two Tibetan groups exceeded 0.35. Moreover, the combined power of discrimination using the 43 deletion/insertion polymorphism loci was calculated to be 0.9999999999999999984 in the Qinghai Tibetan group and 0.9999999999999999921 in the Tibet Tibetan group. The cumulative power of exclusion using the 43 deletion/insertion polymorphism loci was calculated to be 0.999782512 in the Qinghai Tibetan group and 0.999886205 in the Tibet Tibetan group. Analysis of population genetics demonstrated that the two studied Tibetan groups shared close genetic relationships with East Asia populations. Conclusion: The set of 43 deletion/insertion polymorphism loci exhibited remarkable forensic efficacy, rendering it a promising tool for forensic practice. Population genetic analyses indicated that the two Tibetan groups had closer genetic affinities to East Asian populations.