Did Modern Jews Originate in Italy?

Modern Jews may traditionally trace their ancestry to the Holy Land, but a new genetic study finds otherwise. A detailed look at thousands of genomes finds that Ashkenazim - who make up roughly 80% of the world’s Jews, including 90% of those in America and half of those in Israel - ultimately came not from the Middle East, but from Western Europe, perhaps Italy.

Most mainstream historians regard Ashkenazim as the descendants of Jews who moved into central Europe from the Middle East sometime before the 12th century C.E. Ashekenazim, like most members of this religious, cultural, and ethnic group, traditionally trace their ancestry to the ancient Israelites. The Israelites, in turn, arose between 3000 and 4000 years ago in the Middle East, according to both Biblical sources and archaeological evidence. They dispersed after the Romans destroyed their Second Temple in Jerusalem in 70 C.E.

Recent genetic work has supported this traditional view. Two studies, one led by geneticist Harry Ostrer of the New York University School of Medicine, and the other by geneticist Doron Behar of the Rambam Health Care Campus in Haifa, Israel, traced the three main Diaspora groups - Ashkenazim, Sephardim from Spain and Portugal, and Oriental Jews from the Middle East—to people who all lived in the Middle East about 2000 years ago. The Ostrer study used DNA from the nucleus of the cell in its analyses, and the Behar study used both nuclear and mitochondrial DNA (mtDNA); the latter comes from tiny bodies in the living cell that provide it with energy. Many other researchers considered these results to be definitive at the time.

Yet there were lingering questions. Ostrer and Behar had samples from only a couple of hundred Jews, for example. And while the Behar group identified four major mtDNA “founder groups” for the Ashkenazim, all supposedly with roots in the Middle East, it was able to trace only about 40% of Ashkenazi ancestry overall.

So a different team of scientists, led by geneticist Martin Richards at the University of Huddersfield in the United Kingdom, embarked on a new search for the origins of these four founder groups. The team focused on mtDNA, which is often employed in genetic studies because it is easier to sequence and allows analysis of huge population samples. However, mtDNA is inherited through the mother and not the father, so it reveals the history of maternal lineages only.

Geneticists have identified certain mtDNA markers that define lineages in different parts of the world. Behar’s group had traced the Jewish founder groups to two mtDNA genetic lineages called haplogroup K and haplogroup N1b. The Jewish lineages were nested within these two larger groups, which include both Jews and non-Jews. So Richards and his colleagues first set out to understand the history of these broader lineages. They analyzed about 2500 complete and 28,000 partial mtDNA genomes of mostly non-Jews worldwide, plus 836 partial mtDNA genomes of Ashkenazi Jews, to see where the Ashkenazim fit into the overall history.