Analysis of Population Structure in Participants of European Ancestry

<div><p>Analysis was performed without any prior population assignment using STRUCTURE [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.0020143#pgen-0020143-b029" target="_blank">29</a>] (see Methods). The European ancestry groups, western European American (WEURA), central European American (CEURA), eastern European American (EEURA), Finland (FND), Italy (ITN), Spain (SPN), Sweden (SWD), and other European American (OEURA) are indicated by color code. The latter group consisted of individuals with mixed European ancestry from several regions and additional smaller groups (see Methods). The average contribution of each color-coded cluster is indicated by the proportion of the horizontal bars in (A), (B), and (C), whereas in (D), the proportion of each cluster (ordinate) is shown for each individual.</p><p>(A) Analyses were performed with 2,657 SNPs under the condition of two population (Pop) groups (k = 2).</p><p>(B) An analysis is shown for k = 10.</p><p>(C) The results of an analysis using only a selected subset of 400 SNPs is shown for k = 2. These SNPs were selected for potential informativeness for the north–south division in European population structure (see text). None of the participant samples used for selecting this SNP panel (including the Spanish samples) were included in this analysis assessing these same markers.</p><p>Panel (D) Depicts individual participant results under same conditions as (A).</p>