The Y Chromosome Pool of Jews as Part of the Genetic Landscape of the Middle East http://www.sciencedirect.com/science/article/pii/S0002929707...
1 Department of Hematology, Hebrew University–Hadassah Medical School, Jerusalem
2 Hadassah University Hospital, Hebrew University–Hadassah School of Dental Medicine, Jerusalem
3 Laboratory of Biological Anthropology and Ancient DNA, Hebrew University–Hadassah School of Dental Medicine, Jerusalem
4 Institut für Rechtsmedizin, Westfälische Wilhelms-Universität, Münster, Germany
5 Anthropology and Human Genetics Unit, Indian Statistical Institute, Calcutta
A sample of 526 Y chromosomes representing six Middle Eastern populations (Ashkenazi, Sephardic, and Kurdish Jews from Israel; Muslim Kurds; Muslim Arabs from Israel and the Palestinian Authority Area; and Bedouin from the Negev) was analyzed for 13 binary polymorphisms and six microsatellite loci. The investigation of the genetic relationship among three Jewish communities revealed that Kurdish and Sephardic Jews were indistinguishable from one another, whereas both differed slightly, yet significantly, from Ashkenazi Jews. The differences among Ashkenazim may be a result of low-level gene flow from European populations and/or genetic drift during isolation. Admixture between Kurdish Jews and their former Muslim host population in Kurdistan appeared to be negligible. In comparison with data available from other relevant populations in the region, Jews were found to be more closely related to groups in the north of the Fertile Crescent (Kurds, Turks, and Armenians) than to their Arab neighbors. The two haplogroups Eu 9 and Eu 10 constitute a major part of the Y chromosome pool in the analyzed sample. Our data suggest that Eu 9 originated in the northern part, and Eu 10 in the southern part of the Fertile Crescent. Genetic dating yielded estimates of the expansion of both haplogroups that cover the Neolithic period in the region. Palestinian Arabs and Bedouin differed from the other Middle Eastern populations studied here, mainly in specific high-frequency Eu 10 haplotypes not found in the non-Arab groups. These chromosomes might have been introduced through migrations from the Arabian Peninsula during the last two millennia. The present study contributes to the elucidation of the complex demographic history that shaped the present-day genetic landscape in the region.
The Middle East played a crucial role in early human history. Its strategic location at the crossroads of three continents facilitated the movements of peoples and the spread of novel technologies and ideas. At the beginning of the Neolithic period (∼10,500 years ago), the Fertile Crescent of the Middle East was one of the few centers in which the transition from hunting-gathering to permanent settlement and farming took place (Bar-Yosef 1995). Previous genetic studies suggested that demic diffusion of Neolithic farmers, rather than cultural transmission, was responsible for the dispersal of domesticates and technological innovations from the Middle East to Europe, North Africa, and southwest Asia (Cavalli-Sforza et al. 1994; Richards et al. 2000; Semino et al. 2000; Quintana-Murci et al. 2001).
Polymorphisms on the nonrecombining part of the Y chromosome have become powerful tools for the investigation of genetic diversity in males, complementing the information from the maternally inherited mtDNA. Y chromosome variants were shown to be much more localized geographically than mtDNA or autosomal polymorphisms (Seielstad et al. 1998). The study of population history has gained enormous momentum with the recent introduction of a large number of new binary or biallelic Y chromosome polymorphic markers (Underhill et al. 2000). The typing of these markers in a set of worldwide populations led to a comprehensive and detailed Y chromosome phylogeny.
When microsatellites are analyzed within a haplogroup classified by binary polymorphisms, a measure of diversity is added that allows evaluation of interpopulation affinities at fine resolution (Hurles et al. 1999; Helgason et al. 2000; Nebel et al. 2000; Thomas et al. 2000; Kayser et al. 2001). In addition, microsatellite variation provides an estimation of time depth and, hence, facilitates the investigation of the origin and spread of haplogroups and permits placement of the genealogical projections in the context of known or surmised historical events (Zerjal et al. 1997; Hurles et al. 1998; Quintana-Murci et al. 2001). Particular high-frequency modal haplotypes have been shown to be associated with genealogies defined by religious status (Thomas et al. 1998) or surnames that are transmitted along male lines (Sykes and Irven 2000). The Cohen modal haplotype (CMH) has been described as the signature haplotype of the paternally inherited Jewish priesthood (Thomas et al. 1998).
Previous investigations based on binary Y chromosome polymorphisms suggested a common origin for Jewish and non-Jewish populations living in the Middle East (Santachiara-Benerecetti et al. 1993; Hammer et al. 2000). Our recent study of high-resolution microsatellite haplotypes demonstrated that a substantial portion of Y chromosomes of Jews (70%) and of Palestinian Muslim Arabs (82%) belonged to the same chromosome pool (Nebel et al. 2000). Of those Palestinian chromosomes, approximately one-third formed a group of very closely related haplotypes that were only rarely found in Jews. Altogether, the findings indicated a remarkable degree of genetic continuity in both Jews and Arabs, despite their long separation and the wide geographic dispersal of Jews.
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