Assessing the resolution of extended pedigrees using hybridization capture SNP panels: Evidence from real and...

Accurate inference of distant biological relationships remains challenging in forensic genetics. Here, we evaluated a hybridization capture SNP panel for high-resolution pairwise kinship analysis using two extended Han Chinese pedigrees (93 individuals, first to sixth degree). A total of 6049 high-quality autosomal SNPs were obtained, and kinship inference was performed using LR-based and IBS-based methods. Simulations showed that both SNP number and allele polymorphism strongly affected discrimination power, with ≥ 16,000 SNPs enabling near-complete resolution of third- and fourth-degree relatives. In real pedigrees, a panel of 6049 SNPs achieved inference accuracies of 99.69%, 98.26%, and 92.12% for third-, fourth-, and fifth-degree relationships, respectively (log₁₀LR > 0). Genotyping remained robust with 100 pg of input DNA (95% accuracy), supporting applicability to trace forensic samples. Overall, hybridization capture SNP sequencing offers an effective and scalable strategy for extended kinship analysis, with performance further enhanced by expanded high-MAF marker sets.