High-resolution Y chromosome haplotypes of Israeli and Palestinian Arabs reveal geographic substructure and substantial overlap with haplotypes of Jews

High-resolution Y chromosome haplotype analysis was performed in 143 patern ally unrelated Israeli and Palestinian Moslem Arabs (I&P Arabs) by screenin g for 11 binary polymorphisms and six microsatellite loci. Two frequent hap lotypes were found among the 83 detected: the modal haplotype of the I&P Ar abs (similar to 14%) was spread throughout the region, while its one-step m icrosatellite neighbor, the modal haplotype of the Galilee sample (similar to8%), was mainly restricted to the north. Geographic substructuring within the Arabs was observed in the highlands of Samaria and Judea. Y chromosome variation in the I&P Arabs was compared to that of Ashkenazi and Sephardic Jews, and to that of North Welsh individuals. At the haplogroup level, def ined by the binary polymorphisms only, the Y chromosome distribution in Ara bs and Jews was similar but not identical. At the haplotype level, determin ed by both binary and microsatellite markers, a more detailed pattern was o bserved. Single-step micro-satellite networks of Arab and Jewish haplotypes revealed a common pool for a large portion of Y chromosomes, suggesting a relatively recent common ancestry. The two modal haplotypes in the I&P Arab s were closely related to the most frequent haplotype of Jews (the Cohen mo dal haplotype). However, the I&P Arab clade that includes the two Arab moda l haplotypes (and makes up 32% of Arab chromosomes) is found at only very l ow frequency among Jews, reflecting divergence and/or admixture from other populations.