Jews the world over share age-old genetic ties.
The Jews have been not only a national and religious group since the 2nd century BCE but also have common genetic links derived in the ancient Middle East despite their dispersion throughout the world, sophisticated genetic analysis based in New York has concluded.
The study, which was published on Thursday in the online edition of The American Journal of Human Genetics, also provides the first-ever detailed genetic maps of the three major Jewish subpopulations – a precious resource that can be used to study the genetic origins of disease in non-Jews as well.
The important study, called “Abraham’s Children in the Genome Era: Major Jewish Diaspora Populations Comprise Distinct Genetic Clusters with Shared Middle Eastern Ancestry,” was conducted by Dr. Gil Atzmon and Prof. Edward Burns at Yeshiva University’s Albert Einstein College of Medicine and Prof. Harry Ostrer of New York University’s School of Medicine. It also included Prof. Eitan Friedman, head of oncogenetics at Sheba Medical Center at Tel Hashomer, and others.
They performed a genome-wide analysis of Eastern European Ashkenazi Jews; Italian, Greek and Turkish Sephardi Jews; and Iranian, Iraqi and Syrian Jews. A total of 237 participants from diverse Jewish communities in the metropolitan New York region, Seattle, Israel, Athens and Rome underwent blood tests. The 237 Jews were included only if all four grandparents came from the same Jewish community.
The results were compared with a genetic analysis of 418 people from non-Jewish groups around the world.
Jews from the different regions of the world were found to share many genetic traits that are distinct from other groups and that date back to ancient times.
The researchers wrote in the 10-page article to appear in the journal’s print edition that Jews from the major Diaspora groups formed a distinct population cluster, albeit one that is closely related to European and Middle Eastern non-Jewish populations. Each of the Diaspora groups also formed its own cluster within the larger Jewish cluster.
In addition, each group demonstrated Middle Eastern ancestry and varying degrees of mixing with surrounding populations. The genetic analysis showed that the two major groups – Middle Eastern and European Jews – split from from each other about 2,500 years ago.
For more than a century, Jews and non-Jews alike have tried to define the relatedness of contemporary Jewish people, the article states.
“Previous genetic studies of blood group and serum markers suggested that Jewish groups had Middle Eastern origin with greater genetic similarity between paired Jewish populations. However, these and successor studies of monoallelic Y chromosomal and mitochondrial genetic markers did not resolve the issues of within- and between-group Jewish genetic identity.”
The new research, however, showed “distinctive Jewish population clusters – each with shared Middle Eastern ancestry, proximity to contemporary Middle Eastern populations and variable degrees of European and North African admixture.”
Thus, this study demonstrates that European/Syrian and Middle Eastern Jews represent “a series of geographical isolates or clusters woven together by shared identity-by-descent (IBD) genetic threads.”
It also disproved claims of large-scale genetic contributions of Central and Eastern European and Slavic populations to the formation of Ashkenazi Jewry.
“This study provides new genomic information that can benefit not only those of Jewish ancestry, but the population at large,” said Burns, the executive dean and a pathologist at Einstein.
“The study supports the idea of a Jewish people linked by a shared genetic history,” added Ostrer. “Yet the admixture with [non-Jewish] European people explains why so many European and Syrian Jews have blue eyes and blond hair.”
Asked to comment, Prof. Karl Skorecki – director of medical and research development at Rambam Medical Center in Haifa and director of nephrology and molecular medicine at the Technion’s Rappaport Medical School – stated that he was “familiar with this excellent study.”
Skorecki made headlines around the world with his landmark 1997 discovery that the majority of kohanim (Jews of the priestly tribe) were descended from a single common male ancestor, and has conducted extensive research in Jewish genetics.
“I have had discussions with Dr. Atzmon, who visits Israel often and whom I know well. He will be visiting our faculty of medicine and give a lecture on June 9.”
“The goal of the study was to determine a genomic baseline,” said lead author Atzmon. “With this established, we’ll be able to more easily identify genes associated with complex disorders like diabetes that are determined by multiple variants across the genome. Armed with this information, we will be better positioned to treat patients.”
The article notes that Iraqi and Iranian Middle Eastern Jews date from communities that were formed in the Babylon and Persian empires in the 4th to 6th centuries BCE; Jewish communities in the Balkans, Italy, North Africa and Syria were formed during classical antiquity and then admixed with Sephardic Jews who migrated after their expulsion from Spain and Portugal in the late 15th century. Ashkenazi Jews are thought to have settled in the Rhine Valley during the first millennium CE and then to have migrated into Eastern Europe between the 11th and 15th centuries.
“Admixture with surrounding populations had an early role in shaping world Jewry, but, during the past 2,000 years, may have been limited by religious law as Judaism evolved from a proselytizing to an inward-looking religion,” the team wrote.
The study was supported by the Lewis and Rachel Rudin Foundation, the Iranian-American Jewish Foundation, the United States-Israel Binational Science Foundation and private donors.
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