By Paul S. Appelbaum, Diana Muir Appelbaum

from GeneWatch 26-4
Aug-Oct 2013

Perhaps the most interesting aspect of the relationship between genetics and Judaism is how little use both Jewish religious law and Israeli law have made of genetic data on identity issues - despite considerable evidence of shared genetic heritage among most groups of Jews.[1,2,3,4,5]

s.w. anderson / genewatchThis is not to say that the possibility that genetics could identify Jews has excited no interest. The ten lost tribes, after all, are still lost, and have never ceased to intrigue. Old assertions that the Pashtun of the Hindu Kush descend from the lost tribes were revived by the notion that high frequencies among them of Y-chromosome haplogroups R1a1a-M198 and the presence of G2c-M377 may signal a link with ancient Jews.[6] There was international press coverage when genetic testing showed that the Lemba, a Bantu-speaking, southern African tribal people with a tradition of exotic origin, has a high incidence of the Y-chromosome haplotype common among the cohanim, the Jewish priests said to be descendants of the biblical Aaron, Moses' brother.[7] But even if DNA could tell us that the ancestors of the Pashtun, Lemba or some other group were Jewish, it would not ipso facto make their modern descendants Jewish.

Who is a Jew is a complex question, although not more complex than who is British or who is Muslim. Under rabbinic law, a Jew is someone who converted to Judaism or is the child of a Jewish mother.  Israeli citizenship is a separate but interlinked question.  Most Israelis of all faiths are citizens simply because they were born the children of citizens.  Israel has naturalized a diverse array of individuals, including Vietnamese boat people and migrant workers from the developing world, but it is Israel's Law of Return that engages particular attention.

Israel is only one of the many old world countries (others include China, Finland, Ireland, Italy, and Japan) that recognize a "right of return," providing a special track to citizenship for individuals with an ethnic and/or ancestral connection. For historical reasons, Israel framed its law not according to the religious definition of a Jew, but as a deliberate effort to insure that anyone who would have met the Nazi definition of "Jew" is eligible for Israeli citizenship. The Nazi rule was that any person with one Jewish grandparent was a Jew and targeted for extermination. Therefore, Israel admits to citizenship individuals with one Jewish grandparent, even when the individual in question would not be recognized as a Jew under rabbinic law. Israel has given citizenship to about 300,000 immigrants from the former Soviet Union in this category, including some who regard themselves as religiously Christian and ethnically Russian. No genetic evidence was involved, although theoretically, DNA evidence might be presented by a would-be immigrant to prove an otherwise undocumented connection to a specific, known, Jewish grandparent.

Which brings us to the "lost tribes." Unlike the majority of Israelis, the self-described Bnei Menashe of eastern India are observant of Jewish law. They say that their ancestors, the Tribe of Manasseh, wandered so long that they lost knowledge of Hebrew and Jewish law, but in the last generation they have relearned these things: they pray, keep the Sabbath, and teach the Torah to their children.

A single, non-peer-reviewed study of the genetics of the Bnei Menashe published in 2004 indicated some incidence of mitochondrial (i.e., maternal) DNA sequences common in the Middle East.[8] Even if these results were replicated, they would hardly prove Jewish descent. Without a recognized tradition of acceptance as Jews, the Bnei Menashe must undergo conversion in rabbinic courts, which inquire into their sincerity as converts, not whether there is genetic proof of Jewish ancestry. The Jewish commitment of the Bnei Menashe has impressed rabbinic courts; over 2,000 have converted and immigrated to Israel. Many of the estimated 7,000 remaining in India are expected to do likewise. 

The Ethiopian Jews, Beta Israel, by contrast, have a centuries' long history of living as Jews, although detailed descriptions date only to the 19th century. They knew no Hebrew and had no rabbis, but they had partial Bibles and followed Biblical law carefully, observing not only the Sabbath but also laws such as the sacrifice of a Pascal lamb before Passover that other Jews had ceased to follow after the destruction of the Temple in 70 CE.  This, and the fact that they lacked knowledge of Chanukah and were unfamiliar with the Talmud, led to speculation that the community originated as Christians who chose to follow the Hebrew scripture. But the Beta Israel simply explain that they have always been Jewish. Although they lack an origin story like the Bnei Menashe, sympathetic outsiders explain the absence of knowledge of Chanukah (which began around 165 BCE), much less the development of the Talmud (codified around 500 CE), by describing them as the lost Tribe of Dan.

Over the centuries rabbinic authorities have been intermittently aware of the existence of Ethiopian Jews.  In the early 1500s, the question of the Jewish status of an Ethiopian Jewish woman who had been captured either by slave raiders or in war and was purchased as a slave in Egypt came before David ibn Zimra, a highly regarded rabbinic judge in Cairo. He, like rabbis who have considered the problem since, expressed concern about the absence of rabbinic law in Ethiopia; for example, since the Ethiopians did not have formal conversion procedures, the Jewish status of the descendants of converts they may have admitted over the generations and, therefore, of the entire community, was problematic. Nonetheless, he ruled that they are Jews despite their unawareness of post-Biblical law, which he assumed was due to the fact that they were descendants of Dan, lost in the Assyrian conquest of 722 BCE.  In 1984, the Council of the Chief Rabbinate of Israel reiterated the opinion of David ibn Zimra.

Modern Israelis had doubts of a different sort, questioning the Jewishness of a group that not only looked different from other Jews, but was unaware of so much Jewish custom and law.  Nevertheless, when thousands of Ethiopian Jews fleeing civil war after 1979 requested admission to Israel as Jews, they were brought "home" in a series of dramatic airlifts.

Several studies of the genetics of Ethiopian Jews have shown the Beta Israel to be more similar to non-Jewish Ethiopians than to other Jewish communities.[9] They do have Y-chromosome haplotypes Med and YAP+ 4S, common in Jewish populations, and also found among other Ethiopians, but they are unique in not sharing other genetic markers common to the world's large, historic Jewish communities.[10] Over 90,000 Beta Israel have immigrated to Israel. No one pretends that there has not been racism and prejudice, but the community's long history and the traditional approach of rabbinic law trumped doubts based on skin color and DNA.

Concern has been expressed in recent years about the potential for genetic data to assume a privileged position where issues of personal and group identity are concerned. For Jewish and Israeli law to have subordinated genetic evidence to more traditional approaches is thus particularly interesting. 

Diana Muir Appelbaum is an author and historian. She is at work on a book tentatively entitled Nationhood: The Foundation of Democracy, and often writes on topics related to genetic history.

Paul S. Appelbaum, MD, is the Dollard Professor of Psychiatry, Medicine & Law at Columbia, where he directs the Center for Research on Ethical, Legal & Social Implications of Psychiatric, Neurologic & Behavioral Genetics.




1. Behar, D.M., et al. 2006. The matrilineal ancestry of Ashkenazi Jewry: portrait of a recent founder event. Am J Hum Genet. 78(3):487-497.

2. Feder, J., et al. 2007. Ashkenazi Jewish mtDNA haplogroup distribution varies among distinct subpopulations: lessons of population substructure in a closed group. Eur J Hum Genet. 15(4):498-500.

3. Behar, D.M., et al. 2008. Counting the founders: the matrilineal genetic ancestry of the Jewish Diaspora. PloS ONE. 3(4):e2062.

4. Hammer, M.F., et al. 2000. Jewish and Middle Eastern non-Jewish populations share a common pool of Y-chromosome biallelic haplotypes. Proc Nat Acad Sci. 97(12):6769-6774.

5. Nebel, A., et al. 2001. The Y chromosome pool of Jews as part of the genetic landscape of the Middle East. Am J Hum Genet. 69(5): 1095-1112.

6. Lacau, H., et al. 2012. Afghanistan from a Y-chromosome perspective. Eur J Hum Genet. 20:1063-1070.

7. Thomas, M.G., et al. 2000. Y chromosomes traveling south: the Cohen modal haplotype and the origins of the Lemba--the "Black Jews of Southern Africa." Am J Hum Genet. 66(2):674-86.

8. Maity, B., et al. 2004. Tracking the genetic imprints of lost Jewish tribes among the gene pool of Kuki-Chin-Mizo population of India. Genome Biol. 6:PI, available at:

9. Lucotte, G., Smets, P. 1999. Origins of Falasha Jews studied by haplotypes of the Y chromosome. Hum Biol. 71(6):989-93.

10. Hammer, M.F., et al. 2000. Jewish and Middle Eastern non-Jewish populations share a common pool of Y-chromosome biallelic haplotypes. Proc Nat Acad Sci. 97(12):6769-6774.

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