a | Inferred ancestry proportions for 107 sub-Saharan African, 67 East Asian and 81 Western European individuals (filled circles) genotyped for 100 Alu insertion polymorphisms²⁴ (see online supplementary information S1 (data)). The distance between a circle and each side is proportional to the fraction of an individual's ancestry shared with Africans, Asians and Europeans. For many individuals, the proportion of ancestry from a single population is almost 100%. b | Inferred ancestry proportions for the same individuals in a plus 263 individuals from South India. The proportion of ancestry shared with Europeans and Asians varies widely among individuals from South India. c | Inferred ancestry proportions for individuals who identified themselves as African (n = 20), Asian (n = 19) and European–American (n = 20) in the Genaissance panel (see online supplementary information S2 (data)), genotyped for 500 coding SNPs with a minor allele frequency of 10%. The circles are less tightly clustered because the proportion of ancestry among individuals is more varied. For example, one African–American (arrow) is estimated to share ∼60% of his ancestry with other African–Americans and ∼40% of his ancestry with European–Americans. d | A network that depicts the genetic relatedness among individuals from c using 250 SNPs (see online supplementary information S3 (data)). The length of each branch (black lines) is proportional to genetic distance. The distance between any two circles of the same colour (solid lines) is large and contributes to high within-group variance, whereas the distance between clusters (dotted lines) is small and contributes to low between-group variance. Branches that connect individuals with a high proportion of ancestry from more than one population (arrow) are connected directly to the branches between clusters.