Recent research on the Cohen Y chromosome indicates the Jewish priesthood, the Cohanim, was established by several unrelated male lines rather than a single male lineage dating to ancient Hebrew times.Hammer is a University of Arizona population geneticist in the Arizona Research Laboratory's Division of Biotechnology. The study includes such collaborators as Dr. Karl Skorecki of the Technion-Israel Institute of Technology and Rambum Medical Center (Haifa); Dr. Doron Behar, population geneticist and senior physician at the Rambam Medical Center Department of Critical Care Medicine (Haifa), who is also FamilyTreeDNA's Chief mtDNA Scientist and Scientific Advisory Board member, as well as collaborating scientists from Tel Aviv University and the Russian Academy of Sciences.
The new research builds on a decade-old study of the Jewish priesthood that traced its patrilineal dynasty and seemed to substantiate the biblical story that Aaron, the first high priest (and brother of Moses), was one of a number of common male ancestors in the Cohanim lineage who lived some 3,200 years ago in the Near East.
According to the story, a decade ago Hammer and Skorecki were part of the first research group that found the DNA marker signature of the Cohanim - the Cohen Modal Haplotype (CMH) - using a much smaller number of markers. Today, they are able to use a much larger battery of DNA markers and are able to develop a more complete CMH, called the Extended Cohen Modal Haplotype.
Hammer says that the findings should motivate renewed interest in historical reconstructions of the Jewish priesthood as well as high resolution DNA marker analyses of other populations and ‘lost tribes' claiming ancient Hebrew ancestry.
The team was able to pinpoint geographic distribution of a genetically more resolved CMH and "tease apart a multiplicity of male lines" that founded the priesthood in ancient times.
The Extended Cohen Modal Haplotype accounts for nearly 30 percent of Cohanim Y chromosomes from Ashkenazi and non-Ashkenazi Jewish communities and likely traces to a common male ancestor who lived some 3,200 years ago in the Near East. It is virtually absent in non-Jews.
Other lineages that are shared among Cohanim from diverse Jewish communities are distinct from the extended CMH, which reveals, says Hammer, that the priesthood was established by several unrelated male lines.
The Human Genetics journal published the Hammer team's newest findings in their article entitled "Extended Y chromosome haplotypes resolve multiple and unique lineages of the Jewish priesthood."
Some statistics: The team used a sample of 215 Cohanim from various Jewish communities; 1,575 Jewish men from across the Jewish Diaspora; and 2,099 non-Jewish men from the Near East, Europe, Central Asia, and India. Here's a bit of the abstract:
While Cohanim from diverse backgrounds carry a total of 21 Y chromosome haplogroups, 5 haplogroups account for 79.5% of Cohanim Y chromosomes. The most frequent Cohanim lineage (46.1%) is marked by the recently reported P58 T->C mutation, which is prevalent in the Near East.Hammer says that the findings should motivate renewed interest in historical reconstructions of the Jewish priesthood as well as additional high resolution DNA marker analyses of other populations and ‘lost tribes' claiming ancient Hebrew ancestry."
Based on genotypes at 12 Y-STRs, we identify an extended CMH on the J-P58* background that predominates in both Ashkenazi and non-Ashkenazi Cohanim and is remarkably absent in non-Jews. The estimated divergence time of this lineage based on 17 STRs is 3,190 +/- 1,090 years.
Notably, the second most frequent Cohanim lineage (J-M410*, 14.4%) contains an extended modal haplotype that is also limited to Ashkenazi and non-Ashkenazi Cohanim and is estimated to be 4,200 +/- 1,300 years old.
These results support the hypothesis of a common origin of the CMH in the Near East well before the dispersion of the Jewish people into separate communities, and indicate that the majority of contemporary Jewish priests descend from a limited number of paternal lineages.
Read the complete University of Arizona article here and the Human Genetics article here.