In eastern Africa (Fig. 5.5, dimension 1 separates the Afroasiatic and Niger-Kordofanian samples, and dimension 2 separates the Nilo-Saharan samples. As in Fig. 5.3, the Hadza and Sandawe do not separate from the eastern African samples along either dimension to any large extent, although they do cluster closely to each other (Fig. 5.5), and this pattern is consistent with extensive regional gene flow with neighboring populations. The other noteworthy pattern in this plot is the Luo sample (Fig. 5.5), who speak a Western Nilotic language but cluster separately from other Nilo-Saharan speakers along dimension 1, together with Bantu-speaking populations. This clustering is consistent with previous findings that the Luo show predominately Bantu ancestry (Tishkoff et al., 2009) and may reflect high levels of admixture among the Luo and geographically nearby Bantu populations (Bennett, 1983).

FIGURE 5.5 Multidimensional scaling (MDS) (k = 2) analysis of data from Tishkoff et al. (2009). We included eastern African populations with a sample of n ≥ 10, constructed a pairwise distance matrix using (δμ)² (as described in Tishkoff et al., 2009), and the population samples are displayed by linguistic affiliation. The Afroasiatic speakers are shown as open circles, the Nilo-Saharan speakers are shown as triangles, the Khoesan speakers are shown as filled circles, and the Niger-Kordofanian speakers are shown as squares. The Luo population sample is labeled. The x axis represents dimension 1 and the y axis represents dimension 2.