Samples were genotyped with a set of 58 Y-chromosomal binary markers by standard methods20 (Figure 2). These markers define 53 haplogroups (including paragroups), 27 of which were present in the Lebanese sample. We also typed a subset (the first 587 individuals collected, and thus with unbiased ascertainment) with 11 Y-STRs by using standard methods21, 22 (Table S1). STR alleles were named according to current recommendations23, except that “389b” was used in place of “DYS389II”; 398b = (DYS389II − DYS389I).