In Figure 3 a histogram displays the amount of European ancestry in the African American cases, computed with an HMM model described in the Methods. The average European ancestry of the cases was 18% (with a standard deviation of 12%), while the average European ancestry of the controls was 17% (with a standard deviation of 9%) similar to the percentage previously reported [19]. Again, due to the small sample size and the fact that no significant difference in European ancestry was found among cases and controls, stratification was not considered an issue.
