I saw this the other day, but didn’t have time to do a post on it – Supreme Rabbinical Court rules out DNA tests for Jewish status in two cases: https://www.jpost.com/Israel-News/Supreme-Rabbinical-Court-overturns-DNA-testing-for-Jewish-status-twice-595974.
One interesting thing, and important for DNA purposes about Jews is they tend to be an endogamous population (What is Endogamy?*) for the most part. They sometimes marry outside their ethnic group, but it’s not common.
*Endogamy is the practice of marrying within the same ethnic, cultural, social, religious or tribal group. In endogamous populations everyone will descend from the same small gene pool. People will be related to each other in a recent genealogical timeframe on multiple ancestral pathways and the same ancestors will, therefore, appear in many different places on their pedigree chart. Endogamy can be the result of a conscious decision or cultural pressure to marry within the selected group but also occurs as a result of geographical isolation (for example, in island communities).
Examples of endogamous groups include Jews, Polynesians, Low German Mennonites, the Amish, Acadians or Cajuns (French settlers in what is now Nova Scotia, Canada), French Canadians, people from many Arab countries, people from Newfoundland and people from many islands. Endogamy is also a problem in early Colonial American populations.
I have a Catholic friend whose sister fell in love with a Jew and wanted to marry him. His parents said they would only allow him to marry a Jew, but were willing to let him marry a converted Jew. She converted. This will make a difference going forward as the amount of Jewish DNA their four children will inherit is only half the expected amount if the mother was Jewish ethnically. I have Acadian/Cajun roots on some of my maternal grandmother’s lines. My ex-wife grew up in a small town east of Wichita where she joked that she was related to half the town by blood and the other half by marriage, probably a lot more truth to her joke than she realized.
As a result of this endogamy, Jewish DNA has some distinctive markers that show up enough to be considered Jewish. For example, not only do some of my DNA tests have small traces of Ashkenazi Jewish DNA, but my Y-DNA on FamilyTree DNA (FTDNA) has the Cohen Match badge – https://www.familytreedna.com/learn/jewish-dna-testing/cohen-match-badge/.
To the article:
The Supreme Rabbinical Court has overruled two lower courts in recent months to stop them from using DNA tests for Jewish status clarification.
This practice has increased in frequency of late and is controversial since such tests cannot definitively prove Jewish status, only act as an aide, although some rabbinical courts have refused to register for marriage individuals refusing to them.
The use of the tests has been contested by the ITIM religious services group, which appealed both cases to the Supreme Rabbinical Court, and have also invoked the ire of Yisrael Beytenu leader Avigdor Liberman who has labeled their use, principally against citizens from the former Soviet Union, as discriminatory.
The article goes into a lot more depth, but I am concerned that this comment will make it into Israeli law:
He said however that since the Supreme Rabbinical Court has not rejected in principle the use of DNA tests to prove Jewish status he would insist in a future coalition agreement for a law to prevent their use.
There is plenty of evidence that Jewish DNA is unique enough due to so much endogamy that I believe it should be considered if there is a sizeable amount of Jewish DNA present. I am glad the Supreme Rabbinical Court did not outright reject the use of DNA tests. I would say the same holds true for other endogamous populations that have a long history of endogamy.