Map of samples and population structure of North Africa and neighboring populations.

<p>A) On the map, star symbols indicate the location of new population samples and circles indicate previously published samples. The decreasing proportions of Maghrebi ancestry is indicated in a west-to-east gradient of blue across North Africa. An unsupervised clustering algorithm, <i>ADMIXTURE </i><a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002397#pgen.1002397-Alexander1" target="_blank">[25]</a> was used to analyze population structure among 13 African, 2 European and 1 Near Eastern populations based on approximately 300 K autosomal SNP loci in common. The two main gradients of ancestry in North Africa (at <i>k</i> = 8), Maghrebi and Near Eastern, are emphasized with arrows. Other population colors in open circles match the colors displayed in the population structure analysis. B) We plot the full dataset assuming <i>k</i> = 2,4,6,8 ancestral populations. <i>k</i> = 10 and log likelihoods are presented in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002397#pgen.1002397.s001" target="_blank">Figure S1</a>.