Genetic study offers clues to history of North Africa's Jews
Tue, 07 Aug 2012
By Sharon Begley (Reuters)
A new genetic analysis has reconstructed the history of North Africa's Jews, showing that these populations date to biblical-era Israel and are not largely the descendants of natives who converted to Judaism, scientists reported on Monday. The study also shows that these Jews form two distinct groups, one of which is more closely related than the other to their European counterparts, reflecting historical migrations.
The findings are the latest in series of genetic studies, which began in the 1990s, indicating that the world's Jews share biological roots, not just cultural and religious ties. In many cases the analyses have confirmed what scholars had gleaned from archaeological finds and historical accounts.
"This work demonstrates a shared genetic history among the Jews of North Africa and strengthens the case for a biological basis for Jewishness," said medical geneticist Harry Ostrer of the Albert Einstein College of Medicine in New York, who led the study.
For the new analysis, published in the Proceedings of the National Academy of Sciences, Ostrer and his colleagues examined the genomes of 509 Jews and 11 non-Jews from North Africa, which is home to the second-largest Jewish diaspora. Only the European diaspora, which includes American Jews, is larger.
The scientists found that the Jewish populations of North Africa became genetically distinct over time, with those of each country carrying their own DNA signatures. That suggests they mostly married within their own religious and cultural group, said Ostrer. "They lived in ghettos," he said, "so their mobility was quite restricted, and by marrying each other they became as closely related as first cousins once removed."
The analysis showed that all North African Jews are descended from forebears in the Middle East, supporting the hypothesis that biblical-era Israelites among Phoenician traders established colonies along the North African coast.
Common DNA signatures also show that some groups are closer, genetically, to their European co-religionists than expected. That suggests "a shared set of founders," said Ostrer, presumably Jews from the Middle East who migrated west.
If Jewish populations in North Africa and Europe shared ancestors, then Sephardic Jews who settled in Africa after being expelled from Spain during the Inquisition originated in North Africa more than 1,000 years earlier. "The Sephardic Jews show significant North African ancestry," said Ostrer. "That could reflect bidirectional migrations" to and from North Africa and Europe over the centuries.
Exodus from Egypt
DNA evidence lends credence to accounts that in 312 BC Egypt's king settled Jews in Cyrenaica, in what is now Tunisia. According to the Jewish historian Josephus (born in AD 37), by the first century AD there were 500,000 Jews there. The DNA that Tunisian Jews share with those of the Middle East supports accounts that, after the destruction of the second temple in Jerusalem in AD 70, 30,000 Jews were deported to Carthage, in what is now Tunisia.
North African Jews fall into two genetically distinct groups: those of Morocco and Algeria and those of Tunisia and Libya. The former are more closely related to Europeans, suggesting that when the Sephardic Jews were expelled from Spain in 1492 and from Portugal in 1497 most of those escaping to North Africa put down stakes in the first lands they reached rather than traveling farther east.
Experts not involved in the new study saw no major surprises but credited it for the breadth of its findings.
"What's new here is the inclusion of several Jewish communities whose DNA had not been studied before, such as those of Tunisia and Georgia," said geneticist Marcus Feldman of Stanford University, co-author of a 2009 study that found significant genetic similarity between European and Middle Eastern Jews.
Including Georgian Jews led to one surprise: that they are closely related to those of the Middle East, including those in Iraq and Iran. "That shows there was significant migration of Jewish populations along the Silk Road beginning in the Persian Empire," said Ostrer. "Just a small number of founders started Jewish communities in India, Burma, and Georgia."
The Jews of Ethiopia are so distantly related to other Jews that their community must have been founded by only a few itinerants who converted local people to Judaism and then married within the local population. It also suggests the founding was more than 2,000 years ago.
That antiquity helps explain why Ethiopian Jews airlifted to Israel during "Operation Moses" in 1984 had no idea about the holiday of Hanukkah, which commemorates events of the second century BC--long after their ancestors had left Israel.
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