Fig. 4

Panel a displays four intercontinental populations and one mixed population in 2-dimensions. Tetrahedron model in b can be applied to the extended intercontinental analysis. European, Asian, African, and Native American are four distinct populations and denoted in red, green, blue, purple, respectively. Mexican American is mixed population and represented in black. Each intercontinental population has three combinations derived for each face in the tetrahedron. First, FastPop is applied to infer ancestry on each face of tetrahedron and then average proportions over each intercontinental population are used to summarize ancestry