Genetic Ancestry and Disease Risk Stratification in Mixed-Heritage Nigerian Populations Using Admixture Mapping

Admixture mapping exploits differences in disease allele frequencies between ancestral populations in admixed individuals to identify genomic regions linked to disease risk. Mixed-heritage Nigerian populations, arising from inter-ethnic unions across the six geopolitical zones, represent an underutilised resource for admixture mapping of complex diseases. This study applied admixture mapping to stratify genetic ancestry and assess ancestry-specific disease risk loci in a cohort of individuals with documented mixed-ethnic Nigerian heritage. Three hundred admixed participants with self-reported dual ethnic parentage spanning at least two geopolitical zones were recruited from Abuja FCT and Lagos State. Genome-wide SNP data were generated using the H3Africa array, and local ancestry inference was performed using RFMix. Ancestry deconvolution across the genome was correlated with hypertension and type 2 diabetes phenotypes as primary disease outcomes. Ancestry segments from Hausa-Fulani-derived genomic regions were associated with hypertension risk, while Igbo-derived ancestry segments showed enrichment around known T2DM loci. These findings demonstrate the application of admixture mapping in a uniquely diverse Nigerian population context and provide a methodological model for inter-ethnic admixture studies in Nigeria. Keywords: admixture mapping, genetic ancestry, mixed-heritage, hypertension, Nigeria