Jews, Genes and JScreen: What’s New in Jewish Genetics?
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Jews, Genes and JScreen: What’s New in Jewish Genetics?

Ancestry testing services such as 23andMe and AncestryDNA are increasingly popular, with answers to questions about histories that have never been widely available before.

Ancestry testing services such as 23andMe and AncestryDNA are increasingly popular, with answers to questions about families and histories that have never been widely available before.

But genetics is a deep and complex field, and many people have no idea where to dive in. The AJT spoke to experts who offered some of their knowledge about Jewish genetics, how DNA technology affects Judaism and additional risks that come with Jewish DNA.

DNA Testing and Ancestry

In a statement to the AJT, Barry Starr, Ancestry director of scientific communications, explained how a customer’s ethnicity is determined by Ancestry through a “DNA reference panel” and “genetic communities process.”

“The genetic communities process detects groups of AncestryDNA members who are most likely connected, as they share recent ancestors who came from the same region, … or culture,” he said. “Ancestry uses public family trees, ethnicity data, and historical records to determine where this group of people lived and moved over a period of time. As of today, Ancestry can identify up to eight Jewish communities,” Starr said.

Avraham Groll, director of JewishGen — which ensures Jewish continuity for present and future generations — explained that ancestry testing services play an important role for historians alongside traditional research methods.

“Genetic genealogy is certainly considered to be a powerful tool in the arsenal, … and in recent years, much progress and many success stories have occurred due to a combination of technological advancements and a dramatic reduction in cost,” he said.

Jewish Descent

It’s well known that halachic laws of descent follow the mother, and that rule has been set in stone for many generations. DNA testing services raise new questions, but, according to Rabbi Shmuel Khoshkerman of Congregation Ner Hamizrach, DNA is only part of the puzzle.

“DNA cannot be ignored, but on its own, it is not enough to determine Jewish descent,” he said.

Rabbi Michael Broyde is a professor of law at Emory University specializing in Jewish law, family law and law and religion, among other fields. He spoke about the role that mitochondrial DNA testing plays in Jewish descent laws.

“Technology provides data. All law changes as the data gets finer and better and more precise, and halachah is the same,” he said. “The early method of mitochondrial DNA testing is easy: It allows one to identify who the mother is, and then if she is Jewish.

“The second data point is more complex. It is to identify mitochondrial DNA with unique or nearly Jewish ancestry and markers so that one can say that the mother was Jewish, even if one does not know exactly who the mother is.”

In particular, he pointed to a very concrete example of how the testing might be used to answer otherwise difficult questions of Jewish descent.

“A woman or man comes into a synagogue in Poland and says, ‘I think my grandmother was dropped off in a monastery in 1940 and I think she’s Jewish,’” he said. “Until recently, there was no way to verify that. Many Jewish babies were dropped off in Catholic monasteries when Poland was conquered by the Nazis.”


JScreen is a Jewish genetic screening program that, unlike other similar services, can take place in the comfort of your own home. Karen Grinzaid, executive director of JScreen, spoke to the AJT about the importance of genetic screening and diseases that are more common in Jews than in other groups.

Originally, JScreen started as the Atlanta Jewish Gene Screen thanks to Caroline and Randy Gold, whose daughter suffered from Mucolipidosis type IV (ML4), a Jewish genetic disease. They had been screened before their son was born two years earlier, but that screening only included a few Jewish genetic diseases.

“They could have been screened for this condition before, but they weren’t offered comprehensive screening and didn’t know,” Grinzaid said. “They were the ones who worked to make sure that Jewish genetic screening in Atlanta was available and known.”

After two years of that pilot program, the goal was to expand to a more national level, and thanks to advancements in screening technology — most notably being able to test saliva — JScreen’s remote testing kit orders were created.

There are dozens of diseases that are more common in Jewish groups. It is important to remember that certain diseases are prevalent in Ashkenazi Jews while others are common in different Sephardic and Mizrahi communities, Grinzaid said. JScreen’s testing panel includes diseases that occur in all of these groups, and others that are common in non-Jews.

Grinzaid explained that while Tay-Sachs disease is the most widely known condition affecting Ashkenazi Jews, it is not the most frequent.

“The most common is actually Gaucher disease, which a lot of people haven’t heard of,” she said. “This is a condition where about one in every 15 Ashkenazi Jews is a carrier. It’s different than Tay-Sachs because you can have a very mild form, … or have a form where you are very severely affected as a young child. There is also an available treatment for this condition.”

Other conditions common in the Ashkenazi population include cystic fibrosis (1 in 27) and Canavan disease (1 in 55). A list of the more common diseases within the population and all 226 conditions for which JScreen tests is available at

Grinzaid added that services such as AncestryDNA or 23andMe have led to people discovering Jewish ancestry and reaching out to JScreen about their screening.

“We have gotten calls from people who’ve gone through ancestry testing saying, ‘Oh, I think I need to be aware of this,’” she said. “That information can be important, … and many follow-up with genetic carrier testing to determine their risks and plan for the health of their future children.”

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