Tuesday, June 2, 2009

Overturning the Mosaic Law through genetics

The rabbinical law of Israel, or Mosaic Law, considers as Jewish (even if he or she practices another religion, even if he or she doesn’t have a clue) anyone whose mother was Jewish, and who in turn had a Jewish mother, and so on and so forth, straight back to Adam and Eve (or rather, just Eve).

David Goldstein, from Duke University (whom I already mentioned), specializes in the analysis of mitochondrial DNA – that little bit of our genetic heritage that comes down to us exclusively from our mothers, and to them from their own mothers, etc. – that is, by direct matrilineal descent. And ironically, through genetic studies, Goldstein is questioning the traditional matrilineal view of Judaism.

Genetics revealed that there are currently a few scores of haplogroups (genetic lines) of mitochondrial DNA in the world, each one derived from a “founding mother” who lived thousands of years ago (and each one of these mothers being, in turn, a daughter of the “Mother of all Mothers”, the so-called mitochondrial Eve, who lived in Africa some 200 thousand years ago).

Through a genetic analysis of mitochondrial DNA, Goldstein discovered, in 2002, that the mitochondrial DNA of Jewish people appears to be derived from that of local populations living in Europe thousands of years ago – and not from any hypothetical Jewish “ancestral mothers.”

I can illustrate this with my own example: I’m Jewish, and the analysis of my genes shows that I belong to mitochondrial haplogroup H7, a subgroup of haplogroup H, itself the most common haplogroup of people of European ancestry living today, be they Jewish or not.

Meanwhile, the situation is completely different when one considers the Y chromosome, which is inherited exclusively by men, and exclusively from their fathers (women don’t have a Y chromosome, as this is the defining chromosome for males).

Well, in 2000, Michael Hammer, at the University of Arizona, showed that the Y chromosome of Jewish men seems to have come down from a very small number of middle-eastern “founding fathers”, different from those of other populations.

Golsdtein’s theory actually explains the double genetic state of affairs configured by the unspecific characterisctics of mitochondrial DNA and the very specific ones of the Y chromosome.

His theory, as an article in The New York Times explained a few months back, is that European Jewish communities were in fact founded by Jewish men who migrated to Europe from the Middle-East and then married local women. These women weren’t Jewish to begin with: they converted to Judaism as they got married.

The Mosaic Law has thus been overturned by the laws of genetics.

However, in 2006, a team led by Doron Behar, of Rambam Medical Center in Haifa, Israel, discovered – once again, through the genetic study of mitochondrial DNA – that nearly half of Ashkenazi Jews (“German” Jews) in the world today are descended from just four “founding mothers”, most likely Hebrew women from the Middle-East, who lived in Northern Europe, in what is now Germany, one to two thousand years ago. For those Jews, maybe the Mosaic Law still makes some sense.

Anyway, the bottom line is that part of the fist Jews who migrated to the European continent moved from the Middle-East to Europe with their whole family, while others travelled alone and founded a family in loco. Which, far from being unusual, is after all very much your garden-variety immigrant story.

Image: Study for The Great Jewish Bride (credit: Endless Forms Most Beautiful/Flickr)


  1. On the male side, I'd sure like to see a yDNA test for every male who claims Kohen/Levi status..

  2. The Mosaic Law sub commentary in the article are colorful but, of course, not really applicable and you have disproved nothing. Mosaic law is what mosaic law is and whether there was conversions by femails or not is not very relevant to matralineal discent

  3. Actually, you may have unwittingly proved the opposite. If you look at the research paper - High-resolution mtDNA evidence for the late-glacial resettlement of Europe from an Iberian refugium - you'll notice that the percentage of Ashkenazi Jews amongst H7 is disproportionately high when compared to the proportion of Ashkenazi Jews amongst the general European population. While many subclades of H are seen as European in origin (such as H1 and H3), H7 is not one of these and is present in both the Near East and Europe. Further research is required, however, until this research is carried out ‏there is as much chance that the H7 woman from whom you are descended from is of near eastern / Israelite origin as being a European woman who converted to Judaism. Be careful of jumping to conclusions. DNA testing is in its infancy and we really do not know much about what the results mean.

    1. It's just a theory :-) - maybe even a "just so story". Thanks for your comment, Ari.

  4. "Jewishness" didn't begin passing down through the mother until the middle age when rape became so common that the father's lineage was in question whereas the mother's was not. Prior to that it had passed from father to his children as in Biblical times.

  5. H7 is also very present in Caucasus and the Middle East. H is present in Eurasia in general and northern Africa.

  6. H7 was found in a neolithic Unetice culture burial (Central Europe) from 4000 years ago. My ancestress was presumably Saxon.