F_ST estimates for the OLA-typed single nucleotide polymorphisms (SNPs). The site-specific estimate for each of the 20 SNPs typed in the large epidemiological samples is shown, plotted relative to the genomic location of each site in the 5.5-kb sequenced region. The location of the APOE exons within the sequenced region, as presented in Fig. 1, are shown directly below the plot.