Scientists have carried out more frequent and extensive genetic research on Jews than on most other religious or ethnic groups in the world. The main reason for this is medical, as some Jews are in a much greater risk of developing certain genetic or genetically influenced diseases than the majorities in the countries where they are living. This research has also elucidated questions of Jewish history.
As early as the 1990s, two publications in the highly respected scientific journal Nature disclosed genetic confirmation that the Biblical story of the Jewish priests (kohanim) descending form one male ancestor (Aaron) was essentially correct. It was possible to measure that this person lived between 3,250 and 2,100 years ago. A majority of currently living kohanim share a common genetic signature which can be found only in 10-15% of other male Jews.2 This research result was followed by a number of publications on historically interesting, country-specific or other specialized issues of Jewish genetics.3 Finally in 2010 Nature4 and the American Journal of Human Genetics5 published the two so far most comprehensive genetics studies on the origin and migrations of the Jewish people. Two different teams consisting of 32 well-known academic researchers from 8 countries investigated Jewish Diasporas and compared their genome structures to those of non-Jewish groups. Although the two research teams choose different samples of Jews and non-Jews, their main results were identical. “Most Jewish samples form a remarkably tight subcluster…and trace the origin of most Jewish Diaspora communities to the Levant”, wrote Nature.
“most Jewish samples form a remarkably tight subcluster… and trace the origin of most Jewish Diaspora communities to the Levant”
The second article speaks of the “distinct genetics” and “shared Middle Eastern ancestry” of most Jews. Ashkenazi, Moroccan, Italian, Greek, Turkish, Syrian, Iraqi, Iranian and other Jews comprising more than 90% of the Jewish people today “represent genome similarities that are typically seen between distant cousins”, wrote a scientific reviewer of these findings.6 These communities have more genetic links with each other than with the population of their respective host countries. Even when genetic proximity between Jews and non-Jews is discovered, for example between Ashkenazi Jews and South Europeans, which is due to the conversions to Judaism in the late Roman Empire, common ancestry outweighs more recent admixture. More importantly, both studies “are concordant in revealing close relationship between most contemporary Jews and non-Jewish populations from the Levant”7, including Druze, Cypriots, Syrians and Palestinians. The studies found almost no admixture from the regions where the Khazar tribes, said to have converted to Judaism in the 8th century once lived. Others have postulated that modern Jews are not linked to the ancient Jews of Israel, but are offspring of converts, in Europe particularly of those famous Khazars. The new scientific findings unmask these assertions as baseless.
Members of the public, intellectuals and a few religious and political figures reacted emotionally, some with hostility, others with enthusiasm. Many misunderstood or misused them for their own political and ideological ends. As research in genetics and genomics continues, new concerns and also misunderstandings are likely to emerge. These call for a moral compass and a better public understanding of science in general and of the pertinent scientific facts in this case.
Genes do not determine whether a person is a Jew – determinant is family, upbringing, history or choice
The two studies found important traces of ancient Jewish history – of common geographic origin, past migrations and conversions into Judaism – in the current genome structure of the Jewish people. They make no other claims. They do not claim that there is a “Jewish gene”, a frequent and dangerous misunderstanding, or that Jews are genetically different from everybody else. Jews may be unique, but not through their genetic structure, which has much in common with that of others, particularly of people in the Near East. Genes do not determine whether a person is a Jew, determinant is family (in Orthodox Jewish tradition the mother), upbringing, history or choice.
The key question is whether there is a scientific explanation for Jewish sense of group, for the “magic consensus” that Oswald Spengler attributed to the Jews. The discovery of genetic similarities between many Jews, explainable by a common Near Eastern origin raises the question in a new way. Can awareness among Jews that they are “distant cousins”, this time based not on religious tradition but on science, create or reinforce their group solidarity? In general, awareness of common genetic origins or traits may encourage, but can never guarantee common thought or action and does not always generate “altruism” and group solidarity, to use again the terminology of evolutionary psychology.
For the Jews, the answer will be mixed and ambiguous. Some of them will be indifferent because they regard genes and genomes as irrelevant to the problems that the Jewish people and Israel have to face today. Also, they may see it as an issue of only historic interest. In fact, if the numbers of conversions to Judaism increase, then the current genetic markers of common ancestry will be more and more diluted. Other Jews will continue to reject the findings because they do not understand them or for more substantial reasons. They fear that anti-Semites and racists would argue, as in the past, that genetics and genome analysis will make it possible to identify and discriminate against Jews, or they might see a danger that some Jews will propose genetics as a tool to differentiate between Jews.
But for a third group, scientific proof of shared ancestry might encourage more group solidarity and common action as a reaction to growing external hostility. Non-Jews and in a few cases, also Jews who dispute the historic reality and origin of the Jewish people often also question the legitimacy of the State of Israel. The new genetic discoveries could provide a convincing argument to support the historic narrative of the Jewish people. Ignorance about the Jews and their history among a larger global public and the elites can have political impacts which must not be underestimated.
The social sciences have long been reticent to consider genetic explanations of social behavior, and historians have not regarded genetics as one of their research tools. Sociology looks back to a long and bitter “nature versus nurture” debate and generally has desired to see genetics strictly limited to medical research and therapeutic applications. But this view is undergoing a change. The American Journal of Sociology published a supplement on genetics and social structure which asks sociologists and historians to think about the accumulating genetic discoveries as a new “archive” to dig in and think about.8 A commentator greeted this supplement as timely: “If sociologists ignore genes, will other academics – and the wider world – ignore sociology?”9
Historiography and the social sciences must be open to new findings from evolutionary science, genetics, epigenetics and genome research. It is also important to contemplate the enormous philosophical and ethical problems that will arise from some of these discoveries and their possible implications for religion, criminal law, health care, warfare and other issues. In this regard one must reflect upon the advances of behavioral geneticists who are researching the genetic (or epigenetic) roots of certain types of behavior, which inevitably will raise ethical and legal questions.10 Judaism can respond to these questions, like other religions and value systems, and may have some interesting views to put forward, for example with regard to personal versus group responsibility.
The new genetic discoveries could provide a convincing argument to support the historic narrative of the Jewish people
- The genome is the entirety of an organism’s hereditary information. In most organisms, including mammals, it is encoded in DNA. The genome includes both the genes and the non-coding sequences of the DNA (non-coding for proteins). The human genome consists of approx. 23 000 protein-coding genes and many non-coding ones. In 2003 the United States-based Human Genome Project published a complete map of the human genome. Its aim is to understand the genetic make-up of the human species. This has become an indispensable tool of medical research.
- Michael F. Hammer, Karl Skorecki, Sara Selig et.al., “Y-Chromosomes of Jewish Priests”, Nature, Vol. 385, 2.January1997; Mark G.Thomas, Karl Skorecki, Haim Ben-Ami et al., “Origins of Old Testament priests”, Nature, Vol. 394, 9.July 1998
- Among others Doron M. Behar, Ene Metspalu et al., “Counting the Founders: The Matrilineal Genetic Ancestry of the Jewish Diaspora”, PLoS ONE, April 2008, Vol. 3, Issue 4, e2062; Susan M. Adams, Elena Bosch et al., “The Genetic Legacy of Religious Diversity and Intolerance: Paternal Lineages of Christians, Jews and Muslims in the Iberian Peninsula”, The American Journal of Human Genetics, 4.12. 2008, Vol. 83, Issue 6, pp.725ff. A summary of these scientific findings in Diana Muir Appelbaum and Paul S. Appelbaum, “Genetics and the Jewish Identity”, The Jerusalem Post, Internet Edition, 11. Febr. 2008.
- Doron M.Behar, Bayazit Yunusbayev et al., “The genome-wide structure of the Jewish people”, Nature, Letters doi:10.1038/nature09103, 1-5, online 9 June 2010.
- Gil Atzmon, Li Hao et al., “Abraham’s Children in the Genome Era: Major Jewish Diaspora Populations Comprise Distinct Genetic Clusters with Shared Middle Eastern Ancestry”, The American Journal of Human Genetics, 86, 850-859, 11 June 2010.
- Tina Hesman Saey, “Genome maps trace Jewish origins-Roots of far-flung populations reach back to the Levant”, Science News, July 3, 2010, p.13.
- Nature, op.cit., p.4.
- “Exploring Genetics and Social Structure”, American Journal of Sociology AJS, Vol. 114 Number S1 (2008), Introduction pp. vii ff.
- Christopher Shea, “The Nature-Nurture Debate, Redux: Genetic research finally makes its way into the thinking of sociologists”, The Chronicle of Higher Education – The Chronicle Review, Issue of 9.1. 2009.
- There is a growing literature on this question. See e.g. Genetic Testing – Policy Issues for the New Millenium, OECD, Paris, 2000; David Glick and Hermona Soreq, “Ethics, Public Policy and Behavioral Genetics”, in IMAJ, Vol.5, Febr. 2003, pp. 83-86.