Paternal genetic structure and Y-chromosomal haplogroup prediction in the Tujia and Bai ethnic groups of Guizhou, Western China.

backgroundY chromosome genetic markers, with strict paternal inheritance and lack of recombination, are particularly valuable tools for tracing male lineages. They complement autosomal analyses in forensic applications and anthropological inference by increasing resolution for patrilineal structure.

methodsWe genotyped 382 unrelated male individuals from two Tibeto-Burman-speaking populations in Guizhou (Tujia, n = 220; Bai, n = 162) using the Goldeneye DNA Identification System Y Plus kit comprising 44 Y-markers. We calculated haplotype-level forensic indices and assessed inter-population structure via Rst-based multidimensional scaling (MDS) and a neighbor-joining (NJ) tree, based on genetic distances with 47 reference groups. Y-chromosomal haplogroups were predicted from Y-STR profiles to characterize paternal lineages.

resultsIn the Tujia population, 338 alleles and 219 haplotypes were detected, with allelic frequencies ranging from 0.0045 to 0.9364. The haplotype diversity (HD), haplotype match probability (HMP), and discrimination capacity (DC) were 0.9999, 0.0046, and 0.9955, respectively. In the Bai population, 309 alleles and 141 haplotypes were detected, with allelic frequencies ranging from 0.0062 to 0.9691, with HD = 0.9979, HMP = 0.0083, and DC = 0.8704. Population genetic analysis revealed that the Guizhou Tujia and Bai groups share closer genetic affinity with Southern Han than with Northern Han and cluster with Tibeto-Burman-speaking groups, including the Sichuan and Guizhou Yi populations. Similarly, the Y-STR haplogroup prediction results revealed a multilayered paternal structure dominated by haplogroup O2a2, accompanied by contributions from indigenous East Asian lineages and minor inputs from West Eurasia and other regions.

conclusionsOur study provides valuable Y-STR data and forensic parameters for Tibeto-Burman-speaking ethnic groups in China, as well as population genetics evidence in patrilineal history. The Tujia and Bai of Guizhou exhibit a complex paternal genetic structure, offering insights into the demographic dynamics of Southwest China. The 43 Y-marker system exhibits high polymorphism and strong discriminatory power, supporting its utility as a powerful supplementary tool for forensic investigations, particularly for male lineage inference and suspect screening.