Genetic ancestry groups in the modern US population.

(A) ADMIXTURE plot (K = 3) showing the African (blue), European (gold), and Native American (red) ancestry components for individuals from different US population groups. Data are from the 1000 Genomes Project (1KGP) and the Health and Retirement Study (HRS). (B) Distributions of African, European, and Native American ancestry fractions for the three main US genetic ancestry groups defined here: African descendant, Wester European descendant, and Spanish descendant. (C) Principal components analysis (PCA) plot showing the relationships among individuals from reference populations and individuals from the HRS dataset corresponding to the three US genetic ancestry groups. (D) Percentages of individuals from each of the three US genetic ancestry groups are shown for the nine census regions in continental US.