Common genetic threads link thousands of years of Jewish ancestry

Using sophisticated genomic analysis, scientists have probed the ancestry of several Jewish and non-Jewish populations and better defined the relatedness of contemporary Jewish people. The research, published by Cell Press in the June issue of the American Journal of Human Genetics, may shed light on the question, first raised more than a century ago, of whether Jews are a race, a religious group or something else. The genetic, cultural and religious traditions of contemporary Jewish people originated in the Middle East over three thousand years ago. Since that time, Jewish communities have migrated from the Middle East into Europe, North Africa and across the world. The migration of Jews to new locales is known as the Diaspora. This study shows that although Jewish people experienced genetic mixing with surrounding populations, they retained a genetic coherence along with a religious one.

"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," says senior study author, Dr. Harry Ostrer, professor of pediatrics, pathology and medicine and director of the Human Genetics Program at NYU Langone Medical Center. "More recent studies of Y chromosomal and mitochondrial DNA have pointed to founder effects of both Middle Eastern and local origin, yet, the issue of how to characterize Jewish people as mere coreligionists or as genetic isolates that may be closely or loosely related remained unresolved."

To better understand the relatedness of current Jewish groups, Dr. Ostrer and colleagues performed a genome wide analysis of Iranian, Iraqi, Syrian, Italian, Turkish, Greek and Ashkenazi Jews and compared these results with non-Jewish groups. The researchers identified distinct Jewish population clusters that each exhibited a shared Middle Eastern ancestry, proximity to contemporary Middle Eastern populations and variable degrees of European and North African genetic intermingling. The two major groups, Middle Eastern Jews and European Jews, were timed to have diverged from each other approximately 2500 years ago.

"We have shown that Jewishness can be identified through genetic analysis, so the notion of a Jewish people is plausible. Yet the genomes of the Jewish Diaspora groups have distinctive features that are representative of each group's genetic history," says Dr. Ostrer. "Our study demonstrated that the studied Jewish populations represent a series of geographical isolates or clusters with genetic threads that weave them together," added Dr. Gil Atzmonl assistant professor of medicine and genetics at Albert Einstein College of Medicine of Yeshiva University, the study's lead author. "These threads were observed as identical strands of DNA that were shared within and between Jewish groups. Thus, over the past 3000 years, both the flow of genes and the flow of religious and cultural ideas have contributed to Jewishness."

Source: Cell Press