Posted on 01/12/2006 10:33:20 PM PST by ChicagoHebrew
Although they probably weren't named Sarah, Rebekah, Rachel and Leah, four Jewish "founding mothers" who lived in Europe 1,000 years ago have been credited with being the ancestors of nearly half of all Ashkenazi Jews, who constitute the majority of the current Jewish population.
About 3.5 million people - or 40 percent of Ashkenazi Jews currently alive - are descended from these matriarchs, who were among a small group, probably after migrating from the Middle East, according to the Israeli researchers, who also provide evidence of shared maternal ancestry between Ashkenazi and non-Ashkenazi (Sephardi and Oriental) Jews.
The studies that led to these findings were performed by Dr. Doron Behar as part of his doctoral thesis, and were done under the supervision of Prof. Karl Skorecki of the Rappaport Faculty of Medicine and Research Institute at the Technion-Israel Institute of Technology and at the Rambam Medical Center in Haifa.
Skorecki is best known for his 1997 discovery of genetic evidence indicating that the majority of modern-day Jewish men of the priestly tribe (kohanim) are descendants of a single common male ancestor, consistent with the biblical high priest, Aaron.
Researchers from universities in Italy, Estonia, Portugal, France, the US and Russia contributed to the important study, which was published on-line by the prestigious American Journal of Human Genetics on Thursday and will appear in print in the March.
The Technion team's discoveries have significant implications beyond their inherent interest and relevance to human history; they are vital to understanding the mechanisms of genetic health and disease in human populations.
The researchers' conclusions are based on detailed comparative analysis of DNA sequence variation in the mitochondrial DNA (mtDNA) region of the human genome. This type of DNA is transmitted to descendants solely by the mother.
The researchers found that the mtDNA of some 3.5 million of the 8 million Ashkenazi Jews currently living throughout the world can be traced back to only four women carrying distinct mtDNA of a type virtually absent in other populations. Non-Ashkenazi Jews also carry low frequencies of these distinct mtDNA types, thus providing evidence of shared maternal ancestry of Ashkenazi and non-Ashkenazi Jews.
This is consistent with previous findings based on studies of the Y-chromosome, pointing to a similar pattern of shared paternal ancestry of global Jewish populations, originating in the Middle East.
The researchers concluded that the four founding mtDNA - likely of Middle Eastern origin - underwent a major overall expansion in Europe during the last millennium.
The Ashkenazi Jewish population has often been studied by experts in human genetics because of the accumulation of some 20 recessive hereditary disorders that are concentrated in this population, the authors wrote.
The human genome project for mapping human DNA sequence variation has not only made it possible to predict certain genetic diseases, but also the identification of family and genealogical relationships (shared ancestries) among individuals.
The human genome includes some three billion chemical letters (known as nucleotides), which comprise the sequence of nucleic acids in DNA in almost every cell of the human body.
Most of the human genome is diploid, meaning that it has genetic material representing both parents. However, the Y-chromosome carried only by males is haploid (without maternal input), as is mitochondrial DNA, which has no paternal input. Thus geneticists can learn about paternal ancestry from the Y chromosome and material ancestry from mtDNA. As a result, DNA sequence analysis of these two regions of the human genome are important tools in phylogenetics - the study of global populations through genetic analysis.
1000 years ago is roughly when Jews divided into the present day Ashkenazi and Sephardi populations. As for 60-65 years ago, presumably that wouldn't affect this study -- unless the progeny of other women died far more frequently for some unexplained reason.
Ashkenazic ping!
Sounds like you guys are more "diverse" :-)
Google "Hermansky-Pudlak Ashkenazim" and "oculocutaneous albinism Ashkenazim".
Different women will have different numbers of daughters and there's a tendency for some lines to reproduce more prolifically than others. There's a neat little mathematical trick which demonstrates that if you take the total number of women in an isolated group, (say 40), within the same number of generations (40) every female in the group will most likely be descended from just one original female. Using that formula, a group of 160 women could reduce to just 4 lines in 1,000 years. Of course, in the article, it says 40% came from just 4 lines which means there were a lot more than 160 in the original migratory group and there's still plenty of reducing yet to go before you get down to just one line. It's estimated that every woman living today is descended from just one female who lived about 160,000 years ago.
Thanks for the ping...my sister did her mtDNA and I would like to know the haplotypes identified, but the abstract of the article doesn't list it. I will try and get the full text of the article.
They married descendents of Rachel, Leah, Bilhah, and Zilpah... ;) Just kidding. Good question.
I have a very goy question. Are the Ashkenazim the Hasidim? Or are they something different? I'm just surprised to hear one type of Jew constitute half of the Jewish population. Or is Ashkenazim a bloodline more than a religious practice? And some Ashkenazim are Orthodox, some Conservative, some Reformed, etc.?
Oops. Now I see in the title it says Ashkenazim are European Jews! Was that there the whole time? I must be getting old. And tired.
Fascinating.
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Interesting article. Thanks.
Warning! This is a high-volume ping list.
The difference today is mostly in slight differences in religious observance and traditions. Arising out of different Rabbinical authority interpretations.
Communities from various places kept those differences so they account for certain different ethnic Jews being one or the other.
My family history should make us Sephardi but a zig zag in and out of Easter Europe starting about 500 years ago makes us Ashkenazi.
The answer to your last question is yes.
Ashkenazi Jews are those of European descent; Sephardic Jews are from Spain, North Africa and the Mid East-recently, of course, as all Jews except converts and their descendants are originally of Mid Eastern origin. BTW, Ashkenaz is Germany and Sepherad is Spain - that is the origin of these terms.
Religious practice is not genetic or familial in origin - it is up to each person what they do. There are Orthodox, Conservative and Reform Jews who are Ashkenazi, just as members of all three groups can be Sephardic. The Hasidim are almost all Ashkenazi Jews, but relatively few Ashkenazi Jews are Hasidim.
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