The History of Jewish Genetic Genealogy

From Judaism and Science.com (edited)

In 1994-95, three men independently came up with the same idea of testing the Y chromosomes of a limited subset of Jews. 

In late 1994, in England, Robert Bradman was pursuing a graduate degree in genetics and was looking for a research project in Israel where his girlfriend lived. 

Bradman is a Levite by tradition -- a theoretical descendant of the Biblical Levi, third son of the patriarch, Jacob. 

He and his father, Neil, a retired businessman with a background in science, decided to test the story of the Jewish priests.

In January 1995, clinical nephrologist and university professor Karl Skorecki was attending Shabbas service in Toronto. 

The rabbi was looking for a Kohen to say the blessing before the reading from the Torah. 

A Kohen, according to Jewish tradition, is a descendant of the priests who served in the Temples in Jerusalem. 

The Bible sets the inception of the Jewish priesthood to a date several months after the Exodus from Egypt, or, by some accounts, just over 3300 years ago, when Moses presided over the investiture of Aaron as the first Kohen Gadol, or high priest, and his sons as Kohanim (plural for priests). (Exodus. 29:9.) 

The rabbi’s search was answered by a Moroccan Sephardic Jew. Skorecki, of Polish descent, was a Kohen too and he wondered if two people who looked so different were really descended from the same man.

If they were, they should share common genetic markers, which are changes or mutations in a gene.


Bradman and Skorecki independently contacted Batsheva Bonne-Tamir, a professor of genetics at Tel Aviv University, to inquire about the possibility of locating distinguishing markers in the genes of Jewish men. 

Bonne-Tamir encouraged them to contact Professor Michael Hammer, a genetic anthropologist and an expert on the Y chromosome, at the University of Arizona in Tucson. 

Ultimately, the Bradman-Skorecki-Hammer team was formed and a study plan adopted. The purpose of the exercise was not to prove the historical truth of the biblical account of the priesthood, but rather to see whether there was any genetic basis for the Kohen narrative of common ancestry extending back to Aharon. 

Later in 1995, between Rosh Hashanah and Yom Kippur, Bradman’s son Robert collected almost 200 vials containing the saliva of Jewish males, split evenly between those of Ashkenazi (Central and Eastern European) descent and Sephardi (Iberian) descent. About one-third of these men also claimed to be Kohanim. 

When the data was analyzed, the researchers discovered an amazing fact: regardless of the national origin of each of the participants, regardless of their designation as Ashkenazi or Sephardi, they almost all (98.5%) had a relatively unique mutation, called a haplotype, one shared with only 3-5% of the world Jewish population.

This result suggested at least two important things: First, there was a high correlation between the cultural and genetic records and, second, the original possessor of the haplotype pre-dated the millennia old separation of Jews into Ashkenazim and Sephardim. 

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