Rabbi Yehuda Finchas
Blake entered my office visibly excited. “Rabbi, as far as I know, I’m not Jewish. But out of curiosity, I checked my ancestry on the 23andMe website, and it claims that my lineage includes Jewish heritage. Does that mean I’m Jewish? Can I marry a Jewish girl if 23andMe says I’m Jewish?”
What is DNA Testing?
To answer this question, we need to first discuss DNA testing in general and then focus on genetic ancestry testing. Every person has a unique DNA profile, much like a fingerprint. DNA is found in nearly every cell in the body. In recent years, mitochondrial DNA (mtDNA) has become a popular tool for genetic ancestry identification. Mitochondria, the powerhouses of our cells, have their own genetic material, which is passed down exclusively from mother to child. This means mtDNA is inherited along the maternal line and according to halacha it is the mother who determines if the children are Jewish. So, can mtDNA prove you are Jewish?
There are several types of DNA tests. For example, blood tests can detect hereditary diseases such as Tay-Sachs and Cystic Fibrosis, identifying whether a person carries the genes linked to these conditions. DNA testing is also used in forensic science to identify human remains, ensure that all body parts are buried together, and establish identity. Additionally, genetic testing can be used to establish paternity and confirm direct biological relationships. These tests are highly accurate.
Genetic ancestry testing, however, has several limitations. While general DNA tests can accurately determine close family relationships (e.g., parents, siblings, cousins), any connections beyond that are based on probability and statistical estimates.
Jewish DNA?
There is no specific “Jewish DNA.” However, some researchers have found that certain mtDNA haplogroups – groups of related mtDNA sequences – are more common among Jewish populations than in the general population. For example, Nephrologist Karl Skorecki and researcher in molecular genetics Behar write, “At least 40 percent of the Ashkenazi population carry one of four unique forms of mitochondrial DNA (mtDNA)…” In other words, over 3 million Ashkenazi Jews are descendants of four women who were among the founders of the Ashkenazi population. These haplotypes are more prevalent in Ashkenazi Jews and rarely found in Jews of other origins or in non-Jews.
However, these conclusions have been contested as statistically problematic. Since Jewish people make up less than 1 out of 500 people globally, even if a haplotype is much more common in Ashkenazi Jews – say, 100 times more prevalent than in non-Jews – there is still a higher chance that a person with that haplotype is a non-Jewish outlier rather than a Jewish individual.
Other research challenges Skorecki and Behar’s findings. For instance, Professor Raphael Falk from the Hebrew University (2015) concluded that, “genetic markers cannot determine Jewish descent.” Similarly, in 2016, Dr. Eran Elhaik stated that it is impossible to prove Jewish descent using genetic markers and highlighted several issues with current research. Tofanelli’s research in 2014 also pointed out the limitations of using haplotype motifs as reliable indicators of Jewish ancestry.
In Conclusion
In conclusion, there is no clear scientific evidence that one can rely on to determine Jewish descent based purely on genetic testing. Mitochondrial DNA cannot definitively prove that a person is Jewish. While Jewish populations may share certain genetic markers, there is no unique DNA sequence that definitively establishes Jewish ancestry. Therefore, in practice – halacha l’maaseh – Blake cannot rely on his DNA test to prove his Jewishness. If he wishes to marry a Jewish girl, he must establish that his mother or grandmother is Jewish according to halacha.
Jewish people possess special spiritual traits, as reflected in the Gemara (Yevamot 78b), which lists three defining characteristics of the Jewish people: they are merciful, humble, and engage in acts of loving-kindness. The Gemara teaches that anyone who embodies these three traits is truly deserving of our companionship. These are so to speak the spiritual genes of the Jewish people.
Rabbi Yehuda Finchas is a recognized expert, lecturer, and author on Medical Halacha. He is the head of the Torat Habayit Medical Halacha Institute. His latest book is “Brain Death in Halacha and the Tower of Babel Syndrome.” To contact Rabbi Finchas, please email rabbi@torathabayit.com.