The Genetic Legacy of Jewish Catholics

When Francesc Calafell, a geneticist at the Institute of Evolutionary Biology in Barcelona, first began swabbing cheeks as part of an effort to study the genetic makeup of men across the Iberian Peninsula, the project was purely an academic exercise. Together with a team of researchers across Europe, he published a 2008 paper in a well-respected journal, the findings of which surprised everyone, himself included: 20 percent of Catholic men in Spain and Portugal had Y chromosomes that indicated they were of Sephardic Jewish ancestry. “We expected very low numbers because of the pogroms in the 14th century and then the expulsion,” Calafell says, referring to the Spanish Inquisition, which resulted in mass forced conversion and displacement of Jews. “And yet even though ethnically and religiously the Jewish legacy vanished some time ago, it seems that the Jewish genetic legacy in Spain has persisted.”

The results were even more surprising for personal reasons: Calafell’s own Y chromosome indicated that he likely has Jewish ancestors. “It’s a relatively small percentage of my ancestry, but it definitely made me curious,” says Calafell, who was raised Catholic.

Calafell is hardly an anomaly. At the time of the expulsion of 1492, Sephardi Jewry comprised the vast majority of world Jewry, totaling about 400,000 people. “These people didn’t just die,” says Jon Entine, author of Abraham’s Children: Race, Identity, and the DNA of The Chosen People. Their descendants are alive and well today, where they live in considerable numbers across Spain, Portugal, Italy and in large concentrations in what was then hailed as the New World, where many fled in hopes of practicing their faith.

“It’s impossible to say how many people are descendants of Jews, but there are a lot of Catholics running around who have Jewish descent,” says Bennett Greenspan, president and CEO of Family Tree DNA, a genetic testing service. “Certainly, the number of people of Jewish descent is much larger than the number of Jews today.” He says that some estimates put this number as high as 10 million in Brazil alone.

The advent of accessible and affordable genetic testing has buttressed claims of Jewish ancestry, once solely based on anecdotal evidence such as family traditions of lighting candles on Friday night, refraining from eating pork or covering mirrors after someone dies. “Anyone can go online and for about $130 find out a lot of things you want to know—and maybe some things you don’t want to know—about who your ancestors are,” says Michael Freund, founder and chairman of Shavei Israel, which sends emissaries throughout the world to seek out “lost Jews” who may be descendants of Jewish victims of persecution, exile and forced conversion, with the hopes of returning them to the Jewish community. “There are a lot more of us out there than we realize,” he adds.

With Shavei Israel’s help, members of a community in Mallorca, an island off the coast of Spain, have returned to the Jewish fold. The group, known as the Chueta, long held that its ancestors were forced to convert to Catholicism in the 15th century. Genetic analysis confirmed this, leading to official recognition. Last year, Rabbi Nissim Karlewitz, a noted ultra-Orthodox rabbi in Israel, recognized them as Jews, says Freund, allowing them to sidestep a full conversion process.

Rabbi Barbara Aiello hopes to test Italians with possible Jewish roots in Calabria, a hilly region in the toe of Italy’s boot to which Spanish and Portuguese Jews fled, only to face an imported Inquisition. Aiello, who now runs the Italian Jewish Cultural Center in Calabria, was raised as a Catholic in Pittsburgh, but her father, an immigrant from the region, had Jewish roots. As a child, she remembers him looking for three stars at nightfall and saying, “Baruch, baruch, baruch.” On his deathbed, he made her promise that her daughter, his granddaughter, “would not be lost to the Jewish people.” Aiello organizes Shabbat retreats and revives traditions such as Hamishi seder, a crypto-Jewish Passover gathering that was celebrated on the fifth night, rather than first, when it was less likely to be noticed. “We’re all bnei anusim [children of forced conversion] and we had our roots stolen from us,” she says. “There are Jews like me across Italy, and it’s my goal to re-sew them into the tapestry of the Jewish people.”

Increasing numbers of people are taking advantage of testing to expand their knowledge of their family backgrounds. “I can’t explain it, but I can tell you there’s a lot of interest—all the way from a general curiosity [about Judaism] to ‘I want to fight in the Israeli army’ to everything in between,” says Greenspan. At a time of growing secularism and the declining hegemony of the Roman Catholic Church, having Jewish “blood” is seen as a positive rather than a social risk. Freund attributes this to a postmodern need to reconnect with tribalism. “We want to—we need to—identify with people other than ourselves,” he says.

Not everyone who discovers more about his or her past through molecular analysis in a petri dish feels a call to return to the ancestral faith. Calafell, for one, has no intention of converting but welcomes this additional knowledge about his heritage. “DNA is like a ouija board,” says Entine. “People read into it whatever they want. For some, it affirms their identity as a Jew, and for others, it’s just an interesting mosaic, another way to understand human identity. The meaningfulness is somewhat arbitrary. Identity is something we choose. It’s not imposed on us by our DNA.”