Figure 4

Signature of local adaptation on chromosome 7q33. A graphical representation of genotypes is shown for 23 European-American (EA) and 24 African-Americans (AA) across a 115 kilobase region on chromosome 7q33, which encompasses four genes. Rows correspond to individuals and columns denote a particular single nucleotide polymorphism (SNP). For each SNP, blue, red and yellow boxes indicate whether the individual is homozygous for the common allele, heterozygous or homozygous for the rare allele, respectively. Grey boxes indicate missing data. Notice the significant reduction in polymorphism in the European-American sample, which is consistent with the hypothesis that variation in one or more of these four genes conferred a selective advantage to European- Americans but not African-Americans. See Akey et al. [60] for more details. This figure was produced using genotype data from SeattleSNPs project (http://pga.gs.washington.edu/).