A cluster of differentially expressed genes in a region of low nucleotide polymorphism and strong linkage disequilibrium within Europe. (A) Nucleotide diversity (θW) in two African populations (Zimbabwe, dashed line; Zambia, gray line) and a European population (the Netherlands, solid line) along a 22 kb region of chromosome 3R. The genes located in this region are depicted below the plot, with arrowheads indicating the direction of transcription. Gray boxes represent genes that are over-expressed in the African population. The hatched box represents CHKov1, which is disrupted by a Doc element insertion in all of the European lines. (B) Linkage disequilibrium between all pairs of polymorphisms (excluding singletons) within the same 22 kb region in the European population. Values of r2 are indicated in the upper matrix, with r2 ≤ 0.4 (white), 0.4 <r2 < 0.8 (light blue), and r2 ≥ 0.8 (dark blue). The lower matrix indicates the results of Fisher’s exact test, with P ≤ 0.05 (red) and P > 0.05 (white). The arrow indicates the location of the CG10560, CG10562, CHKov1, and CHKov2 gene cluster.