What is the essence of Jewish identity? Is it revealed in the choices we make, like giving tzedakah or observing the Sabbath, or is it in our genetic code? Is it a matter of faith, or a matter of heritability? Is it something we can choose, or is it a biological imperative embedded in nearly every cell of our body?
New genetic research, published as a paper titled “Abraham’s Children in the Genome Era” in the June issue of The American Journal of Human Genetics, highlights the strong genetic bonds both within and among Jewish communities around the world, their distinctiveness vis-à-vis the populations among which they have dwelled, and their links to the Middle East.
For some, findings such as these offer powerful confirmation of the continuity and cohesion of the Jewish people throughout the ages.
“We are a people distinct, as [the biblical figure] Balaam said. We are ‘a nation that will live alone,’” said Rabbi Moshe Tendler, a Yeshiva University bioethicist and rosh yeshiva . “That’s who we are, that’s how God intended us to be.”
“I would like to think this new study is true, because it would indicate that over the course of centuries we still maintain a vast majority of loyal Jews,” Tendler explained. “It is comforting because it confirms a success that no other religion can claim, that there would be inadequate intermarriage to affect the gene pool.”
The steady stream of genetic research into Jewish populations and their origins has sparked widespread discussion of its potential implications for contemporary Jewish identity. Yet the notion that genetics could become a significant factor in Jewish identity is also incendiary for many, with some Jewish thinkers expressing profound discomfort with the idea.
“It smacks of racist and racial innuendo that is suspicious for someone like me in light of the 20th century and the very negative uses to which genetic data was put,” said Rabbi David Ellenson, president of the Reform movement’s Hebrew Union College-Jewish Institute of Religion.
The article “Abraham’s Children in the Genome Era” was based on research by a team of geneticists from leading medical research centers and was co-authored by Dr. Harry Ostrer of New York University School of Medicine and Gil Atzmon of Yeshiva University’s Albert Einstein College of Medicine. While the study broadly echoed many of the findings of earlier Jewish genetic population studies, which looked at maternally inherited mitochondrial DNA or paternally inherited Y-chromosome markers, Ostrer’s team examined 160,000 markers on the entire genome.
Their study looked at the genetic material of people whose origins lay in seven different Jewish communities: Iranian, Iraqi, Syrian, Italian, Turkish, Greek and Ashkenazi Jewries. Researchers compared these groups’ genetic markers to those of other Jewish groups and to those of the local non-Jewish populations. They found far more genetic linkage between Jews within each community than to gentiles from the same areas, and significant linkages between Jews of different communities. The study also demonstrated “distinctive population clusters, each with shared Middle Eastern ancestry.”
“We found a high degree of relatedness among Jewish Diaspora groups. It supports the notion of Jewish peoplehood, that there’s greater relatedness between the Jewish populations than between the Jewish and non-Jewish populations,” said Ostrer, director of the Human Genetics Program at NYU’s medical school and of the Jewish Hapmap Project, which examines the genome structures of global Jewish populations.
A second high-profile study of Jewish population genetics by other researchers appeared in the July issue of the journal Nature. That study similarly found Levantine origins for widely dispersed Jewish communities.
The latest findings about Jewish genes come amid a wave of intense popular interest in population genetics. Researching ancestry through DNA is the focus of two recent television series, one hosted by Harvard professor Henry Louis Gates Jr., and another by actress Lisa Kudrow. There has been a swell of companies, such as Ancestry.com and FamilyTreeDNA.com, eager to sell ancestry genomics tests, which help people trace their individual heritages.
But Steven M. Cohen, a sociologist at the Berman Jewish Policy Archive at NYU who studies issues relating to Jewish identity, drew a distinction between individual ancestry searches and broader associations of genes with peoplehood. He questioned whether genetics would have much of an impact on American Jews’ self-conception.
“American culture has created a Jewish subgroup that is extraordinarily committed to a values conception of what it means to be Jewish, as opposed to the more collective, even tribalist conception that prevails in other countries,” he said.
The frequency of intermarriage has much to do with it, he explained. “It leads both Jewish spouses and Jewish children to adopt a more faith-based conception of what it means to be Jewish,” in order not to exclude the non-Jewish parent, he said.
“It would be ironic and counter-intuitive for younger, postmodern Jews today to embrace evidence that appears to lend support to the idea that Jews are something like a race, or ought to be bound to each other because of some notion of common ancestry,” he explained.
Nevertheless, the implications of recent genetic studies have already infiltrated at least one contentious debate over Jewish identity
In 2008, Tel Aviv University historian Shlomo Sand published a much discussed and highly controversial book questioning the historicity of the very concept of Jewish peoplehood. In the book — published in English last year by Verso, under the title “The Invention of the Jewish People” — Sand argued that Jewish identity is a social construct and dismissed as a myth the idea of the Jewish people having a shared ethnic origin traceable to the Land of Israel.
Reporting on the two recent Jewish population genetics studies, New York Times science writer Nicholas Wade went so far as to argue that their findings “refute the suggestion made last year by the historian Shlomo Sand in his book ‘The Invention of the Jewish People’ that Jews have no common origin but are a miscellany of people in Europe and Central Asia who converted to Judaism at various times.”
Sand, however, was dismissive of the significance of the new genetic research.
“It is a pity and sad that a people have to prove that it is a people by genetics and not by a secular culture,” Sand wrote in an e-mail to the Forward. “The new ‘discoveries’ are not different from the old ones.”
While Sand, who is known for his far-left views, occupies the political margins, many more mainstream figures also believe that genetics should have no bearing on Jewish peoplehood.
“It can point to some interesting data about Jewish marriage patterns and perhaps tell us something about historical patterns of Jewish settlement, but it doesn’t tell us anything about Jewish peoplehood,” said Rabbi Dan Ehrenkrantz, president of the Reconstructionist Rabbinical College.
Similarly, HUC-JIR’s Ellenson said: “I find this type of research interesting but not compelling. Frankly there are cultural and religious reasons that are far more significant to me in terms of affirming Jewish solidarity than genetic claims alone.”
“Jewish peoplehood for me has to do with a sense of solidarity Jews feel for one another worldwide. A sense of connection between Jews has more to do with the internalization of cultural and religious norms than it does a biological kinship,” Ellenson said. “Genetic claims alone are not decisive for most people.”
Others, however, feel more positively toward the significance of genetic findings.
“The religion doesn’t need this confirmatory evidence, but it does enhance people’s belief in religion or can spark an interest in religion,” said Dr. Edward Reichman, an Orthodox rabbi and associate professor of bioethics and education at the Einstein College of Medicine. “It does have some verification, which religious people don’t need, of the historicity of the Jewish people. These are all wonderful things.”
Still, there is wide agreement that genetics do not define whether or not an individual should be considered Jewish.
“There have been people who convert into Judaism — it’s been a regular feature of Jewish life. Those who do are no less Jewish than anybody else. Trying to narrow what it means to be Jewish to carrying particular genetic markers would be a complete misunderstanding of what it means to be Jewish,” Ehrenkrantz said.
Tendler, for his part, said he doubted that rabbinic authorities would ever use genomic ancestry as a measure of someone’s Jewishness. “In Judaism there’s a halachic component as well as a genetic component,” Tendler said. “I don’t think it would ever be used as a test.”
Tendler cited the example of Ethiopian Jews, a group that studies have found lack genetic ties to other Jewish groups. “We don’t believe that they came from the same origin anyway, but rather that they joined our people in the distant past, and that doesn’t make them any less Jewish,” Tendler said.
Still, Ostrer said that the genetic element of Jewish ancestry can be a powerful point of connection.
“I do want people to feel more strongly connected because of my findings. It’s another way of touching the legacy,” he said. “You may have given up corned beef, but you haven’t given up your genome.”