THE MYSTERIOUS CASE OF THE COHENS
By Linda Maria Frank
Everything is relative. And some of us are finding out that we have more relatives in our lives than we thought. In this article, I would like to point out that everything is relatives. Take, for instance, the story of the Cohens, or Kohanim as they are known in the Jewish faith. The Kohanim are males who can trace their lineage back to the first Cohen, who was anointed by Aaron, the brother of Moses, dating back 3,300 years. The line is patrilineal, which means it is passes from father to son through the Y chromosome.
These Kohanim are the “priest family” of Jewish men who conduct Temple services and blessings. The first High Priest’s name was Cohen Gadol, hence the Cohens or Kohanim.
In 1997 Dr. Karl Skorecki, a Cohen descending from Eastern Europeans noticed the physical differences between his group, and Sephardi who hail from Africa, even though both claimed to be descended from Aaron’s first “high priest”. In his capacity as a nephrologist involved in molecular genetics at the University of Toronto, he got the idea of using the latest DNA technology to see if the geographically separated and physically diverse groups of Cohen men had a common ancestor. A point of interest is that this is a protocol of DNA analysis that is similar to that used to profile criminals. (See a previous Guppies Article, When Is a Fingerprint Not a Fingerprint?, Mar. ’13)
In order to test the hypothesis, cheek cell swabs from Cohens (Kohanim) from Isreal, North America and England were collected, along with their family origins. To test the DNA of the Kohanim, the scientists isolated the non-coding portions of DNA on the Y chromosome, looking for mutations which would persist over time, since they are passed from one generation to the next, in this case from father to son. Based on this premise, the collection of mutations that persist should be the same for all the decedents of Cohen Gadol. As we have discussed previously, the results of this analysis can be visualized by using computer programs that produce a graph, (see illustration), where the peaks represent the mutations. These persistent mutations are called markers. The total collection of markers is called a haplotype, and it creates a signature for the group.
The final analysis by Dr. Skorecki and his team noted that a collection of six of the markers was found in 97 of the 106 men tested. These six markers are now known as the Cohen Modal Haplotype (CMH).
Another value of this research is the verification that the common ancestor of the line was a contemporary of Aaron and Moses. Mutations can be used as a clock, since they occur at a predictable rate, the more mutations, the older the sample. Using this concept, the age of Cohan Gadol was determined to be about 3,300 years which coincides with what we know of as the time of Moses and Aaron.
The consistency of the haplotypes among the Kohani is also a testament to the fidelity of their wives, because children produced by another father, but brought up as Cohens, would have a different haplotype.
Another fascinating aspect to this story is the connection between the Kohanim and the Lemba tribe in Africa. The Lemba, who live in Zimbabwe in Southern Africa, practice the traditions of the Jewish religion, those same traditions followed by the Kohanim. They claim to be the Lost Tribe of Israel, a group that migrated from Northern Africa more than 3,000 years ago. In a genetic study similar to the one conducted with the Kohanim, the haplotype of the Lemba priests was shown to be statistically consistent with that of the Kohanim. An interesting conclusion to be drawn from this is that, not only do cultural traditions show relationships between people, but when we look deeper, there may well be a genetic relationship. We seem to be more and more, a very connected species. These studies seem to show us, that everything is relatives.