North African Diaspora written in genes

DNA analysis identifies distinct groups and migrations

Historical Jewish migrations out of the Middle East about 2,000 years ago can also be traced in the DNA of people living in Africa and Southwest Asia today.

These distinctive genetic signatures bolster historical accounts that there were waves of Jewish migration out of the Middle East into neighboring regions. Human geneticist Harry Ostrer of Albert Einstein College of Medicine in New York City and colleagues report their analysis of 509 people from 15 Jewish populations online August 6 in the Proceedings of the National Academy of Sciences, focusing their attention on communities in North Africa, Ethiopia, Yemen and the Caucasus.

Geneticists have previously traced movements of Jewish groups in Europe and the Middle East (SN: 7/3/10, p. 13; SN: 1/3/09, p. 12), but few studies have focused on Diaspora groups in other regions.

Jews settled in Tunisia more than 2,000 years ago, and genetic signatures carried from the Middle East are still evident in Tunisian Jews today, the researchers found. Together with Djerban and Libyan Jews, the Tunisian Jews form a separate genetic branch from Moroccan and Algerian Jews.

Jews in Morocco and Algeria bear genetic signatures characteristic of Sephardic Jews, who once lived in Spain and Portugal. The Spanish Inquisition caused the expulsion of Sephardic Jews from the Iberian Peninsula and many went to North Africa, carrying their genetic heritage with them.  

DNA signatures found in Ethiopian Jews indicate that they are genetically different from Middle Eastern Jews and from the other people living in Ethiopia. The genetic evidence can’t confirm the origin tale that Ethiopian Jews are descendants of King Solomon and the Queen of Sheba, but the findings are consistent with historical accounts that local people were converted to Judaism, then spent more than 2,000 years in cultural and genetic isolation.

Yemenite Jewish people also form a separate genetic group from other Jews, consistent with conversions. “I like to think of it as both the flow of ideas as well as genes that contribute to Jewishness,” Ostrer says.

In the Caucasus, Georgian Jews are an offshoot of groups that first moved from Palestine to present-day Iran and Iraq, the new analysis shows.

Although the new study is the most in-depth of its kind, it certainly doesn’t determine who is a Jew, says Francesc Calafell, a population geneticist at the Institute of Evolutionary Biology in Barcelona. Palestinians have a similar genetic makeup to Jewish people, he points out. “Genetics is only a facet of identity.”

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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