Abstract visualization of DNA results

Who is a Jew? DNA home testing adds new wrinkle to age-old debate

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Part one of our three-part PAST LIVES series on Jewish genealogical research. Parts two and three will be available next week.

Jennifer Ortiz has a screenshot saved on her computer. It’s an image that captures a moment that changed her life.

“Right there on the screen: ‘Stewart Bloom is your father,’” she said, describing the message she received when she logged in to see the results of her home DNA test.

Ortiz is one of millions of people who have taken a DNA test like the ones sold by 23andMe or Ancestry.com. Ortiz, who grew up Catholic in Utah, found out from the test that she was 50 percent Ashkenazi Jewish — a result that led to the discovery that she was the child of Bloom, a Jewish photographer in San Francisco, and not the man who raised her.

“That’s when my world changed,” she said.

But what is 50 percent Jewish?

The question itself is a new wrinkle in the age-old debate of just what it means to be Jewish, which has been given a kick in the pants from the commercialization of a field of science that says it can tell you something new: For a price, you can now choose from one of seven commercial genetic tests to find out just how Jewish you are (among other things).

“It’s a very interesting, different and complicated and morally ambiguous moment,” said Steven Weitzman, director of the Katz Center for Advanced Judaic Studies at the University of Pennsylvania and former director of the Taube Center for Jewish Studies at Stanford University.

In the past few years, commercial gene testing has taken off, driven by aggressive advertising that purports to tell the real story behind your ancestry. The magazine MIT Technology Review analyzed available data to estimate that more than 26 million people had taken at-home tests since they first went on the market more than a decade ago.

“It’s really beginning to seep into people’s consciousness,” Weitzman said.

Sunnyvale-based 23andMe and Ancestry.com, headquartered in Utah, will ask you to spit in a tube and then, several weeks later, will give you a pie chart that might say, for example, 20 percent Swedish, 8 percent Greek and 11 percent German. Or, perhaps, 39 percent Ashkenazi Jewish.

But is there such a thing as 39 percent Ashkenazi? Yes, according to professor of epidemiology and biostatistics Neil Risch, director of UCSF’s Institute for Human Genetics.

Neil Risch delivering the keynote at the American Society of Human Genetics conference in 2015. (Courtesy American Society of Human Genetics)
Neil Risch delivering the keynote at the American Society of Human Genetics conference in 2015. (Courtesy American Society of Human Genetics)

“It’s very easy to identify someone who’s Ashkenazi Jewish,” said Risch, who also does research on population genetics for Kaiser Permanente Northern California.

That’s because there are genetic markers distinct to the Eastern European Jewish population, partly due to a population “founder effect,” a way of saying that they descend from a small number of ancestors. Also, Jews in Europe tended to marry other Jews, making them endogamous.

“Jews were not allowed to intermarry,” Risch said. He added that on top of that, there were other external factors; for centuries, Christian churches forbade their flock from marrying Jews.

Ashkenazi Jews share a genetic profile so distinct that even commercial tests can spot it, unlike the difference between, say, Italians and Spaniards, who share a more diffuse Southern European profile. Risch said that although commercial genetic tests will show a percentage of your heritage from very specific regions in Europe, these results should be taken with a grain of salt.

“Those kinds of subtle differences are challenging and have to be looked at with some skepticism,” Risch said.

“I call it entertainment genetics,” said Marcus Feldman, a Stanford biology professor and co-director of the university’s Center for Computational, Evolutionary and Human Genetics, “when you go and find out where your ancestors came from.”

Marcus Feldman
Marcus Feldman

But for Ashkenazi Jews, heritage is pretty clear. Pick a street, Feldman said. Then pick any two Ashkenazi Jews at random walking down it.

“They’d be fifth to ninth cousins at the genetic level,” Feldman said. Ashkenazi Jews are actually that closely related, all descended from a small group of people.

But what about Sephardic Jews looking to get a quantitative peek at their heritage? They’re out of luck. 23andMe communications coordinator Aushawna Collins said that the company hasn’t collected enough data on those populations yet to be able to pinpoint what makes them unique in terms of genes. Risch said it’s because genetically they are not distinct enough from other Mediterranean peoples.

But even if science can determine whether people have Ashkenazi genes, can one extrapolate from that how “Jewish” they are?

“What is 39 percent Jewish? That’s nonsense,” said Weitzman, a former professor of Jewish culture and religion at Stanford, where in 2012 he started an interdisciplinary course on Jewish genetics with biology professor Noah Rosenberg. “You can’t be half Jewish. You’re either Jewish or not Jewish.”

Rabbi Yehuda Ferris of Berkeley Chabad would agree.

“You can’t be part kosher, you can’t be part pregnant, you can’t be part Jewish,” he said.

However, even Ferris and his wife, Miriam, have done at-home DNA tests — although they did it to find relatives, not to figure out their Jewishness.

“It was extremely shocking,” Ferris said dryly. “I’m 100 percent Ashkenazi Jewish and she’s 99 percent.”

“For zero dollars we could have told you the same thing,” Miriam Ferris added.

Rabbi Yehuda Ferris
Rabbi Yehuda Ferris

As an Orthodox rabbi, Ferris goes not by percentages but by the matrilineal rule in establishing Jewishness.

“If your mother is Jewish, you’re Jewish,” he said. “That’s it.”

The concept of matrilineal descent is an old one, but genetics are giving it a new twist, especially in Israel where the Chief Rabbinate has used gene testing to weigh in on the crucial question of who is a Jew. (In Israel, immigrants must prove their Jewish status to marry, be buried in a Jewish cemetery or undergo other Jewish life-cycle rituals.)

“That’s an interesting and disturbing new phenomenon,” Weitzman said.

The way the rabbinate has used gene testing is by examining mitochondrial DNA, which gives much less information than testing of the more extensive DNA in the cell nucleus, which is what home tests do. But unlike nuclear DNA, mitochondrial DNA is almost always passed from mothers to their children. This dovetails nicely with the notion of matrilineal Jewish descent, and rabbis in Israel have now begun accepting mitochondrial DNA testing for people, primarily immigrants or children of immigrants from the former Soviet Union, who have inadequate documentation of their Jewish status.

The test can identify Jews descended from four “founder” women ancestors. However, it can be used only to prove a positive, as half of Ashkenazi Jews don’t have the characteristic mitochondrial chromosomes at all. Still, for people who have no paper or eyewitness proof of Jewish descent, genetic testing can be the deciding factor.

“When you don’t have enough information, it might be the linchpin,” Ferris commented.

The rabbinate’s use of mitochondrial DNA testing is controversial, with some critics calling it humiliating. The Yisrael Beiteinu party, which represents Russian-speaking immigrants, is trying to challenge it in Israel’s Supreme Court.

Outside of Israel, too, not everyone is comfortable with using science to figure out who is a Jew. It’s something the world has seen before.

Steven Weitzman
Steven Weitzman

“People were also using ‘science’ to figure out who people were. We called that ‘race science,’” Weitzman said.

And the people who did it?

“I mean Nazis,” he clarified.

“Genetics have been used against Jews in the most virulent way,” said UCSF’s Risch. But he thinks that Jews are inclined right now to trust the science because it’s a field filled with Jewish researchers. “We love science because we’re all the scientists!” he said.

In the past two decades, there has been a rash of research on the genetic components of Judaism, a boom coinciding with the Human Genome Project, which ran from 1990 to 2003. Much of it was done by Jewish scientists. The initial research on mitochondrial DNA in Ashkenazi Jews was done in 2006 by Israeli geneticist Doron Behar; he is now CEO of genetic analysis company Igentify.

In 1997, a study of traits in the Y chromosome, passed only from father to son, found that more than 50 percent of men with the last name Cohen (or Kahan or Kahn or other variants) had a certain marker, giving some support to the idea of a hereditary Jewish priesthood.

In 2010, medical geneticist Harry Ostrer did work that found various communities of Jews shared a common Middle East ancestry. And in 2009, Feldman, who is also director of Stanford’s Morrison Institute for Population Biology and Resource Studies, studied to what degree Jewish groups in different places were related. (This last topic has been studied further, including by Risch.)

But Feldman himself has experienced firsthand how his own research has been twisted for what he called “racist” conclusions — when economists drew inferences from his work with fellow Stanford professor Rosenberg to suggest there’s a genetic basis for economic success.

“We were outraged because those two people were using our data to make these quite racist statements,” Feldman said.

Feldman said it’s common for the public to seize on genome research and try to use it to explain everything from intelligence to criminality; he said scientists have a responsibility to be “on alert” all the time.

“There’s been too much emphasis on the genetic basis of a lot of human behaviors,” he said. When genetics is your hammer, “everything becomes a nail,” he said. “So it doesn’t matter what human trait you’re interested in.”

Even if geneticists like Feldman consider home testing kits entertainment, their popularity shows that people are interested in using genetics to figure out who they are, including “how Jewish.” Weitzman said it might be connected to how hard it is for most Ashkenazi Jews in this country to trace their roots; Jews in Central and Eastern Europe didn’t have last names until the 18th or 19th centuries.

“A lot of us, we don’t know a lot about our ancestors prior to our grandparents,” Weitzman said.

So in searching for ancestors, people are turning to the companies that promise results. 23andMe’s Collins told J. they’d sold 10 million kits in total, and Ancestry.com in May issued an announcement claiming to have tested more than 15 million people.

Cantor Doron Shapira of Peninsula Sinai Congregation in Foster City is one of them. He was always into Sephardic music and food. As a percussionist, he felt drawn to the rhythms.

Cantor Doron Shapira in his office at Peninsula Sinai Congregation. (Photo/Gabe Stutman)
Cantor Doron Shapira in his office at Peninsula Sinai Congregation. (Photo/Gabe Stutman)

“People have very often asked me, ‘Are you Sephardic?’” he said. “And I always said, ‘Not to my knowledge.’”

Last year he saw an ad for Ancestry.com, got his DNA testing kit and sent it in with his sample.

“It comes back 94 percent — no surprise — Russian Ashkenazi Jewish European roots,” he said.

But the test also revealed 6 percent of his roots were “other,” including from Southern Europe and the Iberian Peninsula. Maybe Shapira had a Sephardic ancestor after all?

He started to think about which side of the family it could be and considered asking his mom to get tested. It wasn’t that the result suggesting a Sephardic ancestor changed his perception of who he was, he said, but it validated something about himself that he — and others — had always noticed.

“I got a little bit excited,” he admitted.

And then he got an email update from Ancestry.com.

“It says, scratch that, you’re now 100 percent Ashkenazi Jewish,” he said with a laugh.

But even with the change in result, Shapira says he’s not against using home genetic testing to get a peek into his ancestry.

“I’m inclined to do another one,” he said. “Just to see if it’s consistent.”

Many others are taking the tests and their results very seriously. “People are making life decisions now on the results of this test,” Weitzman said. “They’re deciding whether they’re Jewish or not.”

That’s what Ortiz has done. If you ask her now if she’s Jewish, the 53-year-old has an answer.

“Yes, I am,” she said. “I’ll say yes.”

She had never been told that the father who raised her was not her biological dad, and when she confronted her parents, they denied it. But she knew it was no mistake when the DNA testing company delivered a startling message with the name of her biological father — that’s the screenshot she’s got saved on her computer.

Jennifer Ortiz and father Stewart Bloom, minutes after they first met. (Courtesy Ortiz)
Jennifer Ortiz and father Stewart Bloom, minutes after they first met. (Courtesy Ortiz)

Ortiz immediately made contact with Stewart Bloom and flew down to San Francisco last year from her home in Portland to visit. There was a lot to process, of course, but for Ortiz it’s been a wonderful thing — and that includes embracing Jewishness, something she said she’d always been drawn to.

“When I found out I’m actually 50 percent, on one level it didn’t surprise me,” she said.

Now she’s converting that number into something deeper: She’s planning a ceremony in Portland with a Jewish Renewal rabbi — not a conversion, but something to celebrate her new identity.

“It would help me take a step into Judaism,” she said. “Not just from a biological level but a little more than that.”

Thinking about Jewishness in terms of biology is something that bothers Emma Gonzalez-Lesser, a Ph.D. candidate at the University of Connecticut and the author of an article titled “Bio-logics of Jewishness.” If being Jewish is something in the genes, then that excludes people who have come to Judaism in other ways.

“People who convert may not be seen as legitimately Jewish as someone who has 30-something percent ancestry from a genetic test,” she said.

And beyond that, she added, there are some ideas underlying the current fascination with genetics that aren’t being questioned, like the question of whether Jews are a race.

“I think part of our societal fascination with genetic testing really rests on this assumption that race is really this biological function,” she said.

(Prominent researchers like Feldman, Rosenberg and Risch have been caught up in the sensitive question of whether studying the genomics of populations leads to a biological definition of race; the issue has been written about at length and remains controversial.)

Weitzman said the interest in ancestry reflects a trend around the world of turning to biology, genetics and race as a way to encode identity.

“Part of what’s going on in the Jewish world right now is a reflection of a broader revival” of ethno-nationalism, Weitzman said.

In addition, at a time when American Jews are less likely to go to synagogue or practice rituals in the home, they face more questions about what it means to be Jewish. That may incline them to trust in science to determine their identity, especially when they have only a few dusty boxes of papers, if that, to show their family history. That makes “Jewish genes” a door into the past.

“There’s something hiding inside of you that is preserving your identity intact,” Weitzman said. “To me, that’s part of the appeal.”

Maya Mirsky
Maya Mirsky

Maya Mirsky is a J. Staff Writer based in Oakland.