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Tuesday, August 11, 2009

Jewish priesthood founded on limited paternal lineages

A new study of the Jewish priesthood (Cohanim) suggests the majority of contemporary Jewish priests descend from a limited number of paternal lineages, the 2 largest being in J1e (P58) and J2a (M410). Over 60% of Cohanim descend from one of these 2 paternal lines. Unfortunately the paper did not test for newly discovered SNP's L24 and L25 (rs35248080 and rs34534058), known to be found in a large set of J2 Ashkenazi Cohanim. These haplotypes were simply defined as J2a, M410 in this paper. The study identifies 2 principal founding lineages for Jewish priests, one in J1e (P58) dating back to a common ancestor who lived approximately 3190 years ago and another lineage in J2a (M410) dating back to a common ancestor who lived 4200 years ago. It is also interesting to see a 3rd lineage of Jewish priests from the island of Jerba defined by SNP M318 which also lies downstream of SNP's L24 and L25, also known as J2a4h.

The study was a long overdue followup to a 1997 study which identified a 6 marker Cohen Modal Haplotype. This new paper identifies an expanded 12 marker haplotype in J1 found in a large portion of Cohanim who carry the Y-Chromosome M267 (J1) SNP. The study also showed the likelihood of both the J1e and J2a genetic signatures dating back to before the Jewish diaspora since both signatures were found in Jewish communites from the Near East, Eastern Europe and the Mediterranean, communities which have been, for the most part, separated since roman times.

1 comment:

Anonymous said...

The cited paper is remarkable with respect to haplogroups and haplotypes typing and the large number of individuals tested, including Cohanim, which is the prime target of the study. However, it is open to critique regarding calculations of time spans to common ancestors of presented series of haplotypes. First, the authors have employed an inadequate methodology for the calculations, namely the infamous ‘‘pop ulation mutation rates’’ of 0.00069 mutation/marker/ generation. It should not have been used in the first place. More adequate procedures have been developed lately. Second, the authors have not defined criteria when the ‘‘population’’ and when the ‘‘pedigree’’, or the ‘‘genealogical’’ mutation rates, should be used. As a result, they have applied the ‘‘population’’ mutation rate to ‘‘genea logical’’ haplotype series, which increased their ‘‘TMRCA’’, i.e., a time span to common ancestors, by about 300%. Third, they have not analyzed genealogical lineages with recent common ancestors (such as 500– years bp); therefore, they missed valuable information regarding history of Cohanim in this millennium.

Conclusions Cohanim J1e*-P58* 322

A common ancestor of all 99 Cohanim lived 1,075 ± 130 ybp, and this timing is reproducible for 9-, 12-, 17-, 22- and 67-marker haplotypes. A much higher values of 3,190 ± 1,090 and 3,000 ± 1,500 ybp were obtained in the cited paper (Hammer et al. 2009) using incorrect methods and incorrect mutation rates. A common ancestor of all the 99 J1e* Cohanim lived around the tenth century AD. There are three main lineages derived from the common ancestor, with their common ancestors who lived approximately between 625 and 875 ybp.

An emphasis of the cited paper on the conclusion that ‘‘an extended CMH on the J1e*-P58* background that…is remarkably absent in non-Jews’’ and having ‘‘the estimated divergence time of this lineage… 3,190 ± 1,090 years’’ is incorrect regarding the divergence time. It is more understandable why the lineage originated only 1,075 ± 130 years ago is ‘‘remarkably absent in non-Jews’’.

Cohanim J2a-M410* Common ancestors of 31 Cohanim lived 325 ± 190 and 375 ± 110 ybp (recent different DNA lineages), and their common ancestor lived around 1,500 ybp. A common ancestor of another branch of Cohanim of this haplogroup lived 3,560 ± 830 ybp, and yet another common ancestor lived about 6,200 ybp.

Cohanim J2b-M12 348 Common ancestors of 15 Cohanim lived 3,150 ± 600 and 1,050 ± 290 ybp, with the second lineage being descendant from the first common ancestor.