Kohen - Kohen Genetic Testing

Kohen Genetic Testing

Recently the tradition that many Kohanim are descended from a common male ancestor has gained support from genetic testing. Since the Y chromosome is inherited only from one's father (women have no Y chromosome), all direct male lineages share a common haplotype. Therefore, testing was done across sectors of the Jewish and non-Jewish population to see if there was any commonality among their Y chromosomes. The initial research by Hammer, Skorecki, et al. was based on a limited study of 188 subjects, which identified a narrow set of genetic markers found in slightly more than 50% of Jews with a tradition of priestly descent and approximately 5% of Jews who did not believe themselves to be Kohanim. Over the succeeding decade, Hammer, Skorecki, and other researchers continued to collect genetic material from Jewish and non-Jewish populations around the world. This led to the classification of a broader set of genetic markers, now termed the Cohen Modal Haplotype (CMH). The most recent results suggest that 46% of those who have a family tradition of Priestly descent belong to the Y-DNA haplogroup identified as J-P58, and that at least two-thirds of that 46% have very similar Y-DNA sequences indicating comparatively recent common ancestry. A further 14% of Kohanim were found to belong to another lineage, in haplogroup J2a-M410. In contrast, the original CMH is found in as much as 5% to 8% of Jews who have no family tradition of being Kohanim, and only 1.5% were found to have the closest match to the most detailed sequence. Amongst non-Jews the CMH can be found among non-Jewish Yemenites (13%) and Jordanians (~7%), but none were found to most closely match the most detailed sequence. Thus, peer-reviewed studies in the scientific literature document certain distinctions among the Y chromosomes of Kohanim, implying that a substantial proportion of Kohanim share some common male ancestry. Since the religious status of a Kohen is contingent upon being the male biological descendant of Aaron in conjunction with numerous other variables that are not subject to genetic testing (the wife of a kohen cannot have had relations with a non-Jew, be a divorcee etc.) the possession of a common haplotype does not provide sufficient evidence to confer or maintain the religious status of a Kohen, which depends on more than simple heredity. This loss of priestly status over time may account for the 1.5% of non-Kohen Jews who very closely match the Y chromosome sequence that is most common amongst Kohanim.