Book Review - Legacy: A Genetic History of the Jewish People by Harry Ostrer. (Oxford University Press, 2012)
Harry Ostrer is a distinguished medical geneticist at Albert Einstein College of Medicine whose new book, Legacy: A Genetic History of the Jewish People, is not nearly as good as it could - or should - have been.
Part of the difficulty arises from Ostrer's tendency to make un-nuanced assertions. The book opens with the statement: "In June 2010, I published a scientific article that demonstrated a biological basis for Jewishness."
Ostrer is referring to the findings of his 2010 study, "Abraham's Children in the Genome Era: Major Jewish Diaspora Populations Comprise Distinct Genetic Clusters with Shared Middle Eastern Ancestry," which appeared within a month of a study by an Israeli group led by Doron Behar, "The Genome-wide Structure of the Jewish People." Both studies compared DNA microarray analyses of Jews whose recent ancestors lived in a variety of Jewish communities scattered across several continents. The data for these Jewish communities, all of which had strong traditions of endogamy, were compared with existing data on West Eurasian populations.
The Behar et al. study looked at a wider assortment of Jewish communities, while Ostrer et al. sampled a larger number of individuals, but the two came to remarkably similar conclusions. Most of the communities of the diaspora, and all of the largest communities, are more closely related to one another than they are to the populations of the countries in which they have lived for centuries or millennia. This despite the fact that they were spread from Lithuania to Yemen, ranged from short and swarthy to tall and blue-eyed, and in many cases had limited opportunities for contact with one another for the better part of two millennia.
The non-Jewish population to which Jews can at present be shown to be most closely related is the Samaritans, an ethno-religious group that most people associate with the New Testament parable of the "good Samaritan." Samaritans are understood as originating in an ancient (first millennium BCE) schism within the Jewish community in Palestine. The group, which follows the law of the Torah but not rabbinic Judaism and never left the land of Israel, practices endogamy and has shrunk over the millennia to a mere handful of families. Genetic mapping also shows high overlap between Jews and Druze, another indigenous, endogamous Levantine ethno-religious group, and with Cypriots. Jews and Palestinians are less closely related, not only because Jews mixed with other populations during the long diaspora, but also because Palestinian Muslims have substantial non-Levantine ancestry.
There is interesting work still to be done. It would be interesting to compare Jewish markers with those of more populations historians regard as most likely to have continuously resided in the Levant, such as Palestinian Christians, Maronites, and Aramaic-speaking Christians. But we may be able to get even closer to knowing what the ancient Jewish gene pool looked like by examining DNA from Jewish burials in the Roman catacombs or graveyards in Palestine such as Beit She'arim.
These fine-grained details would be interesting to see, but the debate over whether Jews can claim significant Middle Eastern descent is settled. DNA evidence of Jewish peoplehood and Near Eastern origins corroborates the evidence of Jewish unity and cultural continuity in the linguistic, historical and archaeological record. Less than twenty years ago almost all historians assumed that while Jews shared a unique cultural heritage traceable to origins in the hill country of Judea, they shared most of their ancestry with the peoples among whom they lived. These assumptions have been overturned by the work of Ostrer and others demonstrating that Jews from every continent share genetic markers with surprising frequency. Racists, of course, always suspected something of the sort.
None of this, however, suggests that there is a biological basis for "Jewishness," whatever that vague entity might be. As the genetic data and the historical record make clear, no small number of non-Jews has joined the Jewish people over the last several millennia. Ruth, the Moabite ancestor of King David, may have been the most widely publicized convert, but she was by no means the last. Debates over whether Jews are best understood as constituting a religion or a nation may continue forever, but neither category has a biological basis.
Ostrer also exhibits a disappointing proclivity for overreading the import of his findings for contemporary geopolitical dilemmas. This is why readers will be troubled by Ostrer's assertion that "the stakes in genetic analysis are high," because genetic evidence lies at "the heart of Zionist claims for a Jewish homeland in Israel."
This is a problematic assertion for several reasons, of which the simplest is that Ostrer conflates the claim to a national homeland made by pre-state Jewish nationalists and the right to sovereignty on the part of an existing nation state. More troubling is Ostrer's assertion that investigation of where one's ancestors lived upwards of 2000 years ago is relevant to the rights of nations-a standard that would leave few contemporary nation states on firm footing. Ostrer "can imagine future disputes about exactly how large the shared Middle Eastern ancestry of Jewish groups has to be to justify Zionist claims." It doesn't require much imagination. One only has to look at the emerging use of genetic information for similarly dubious purposes, for example the Hungarian Member of Parliament from the Jobbik party who hired a genetic testing laboratory to certify that he is free of Jewish and Roma (Gypsy) genetic markers.
The Zionist claim was not based on genetics; it was based on the liberal political principle that sovereignty resides in the people. The claim that Israel is the territory in which Jews are entitled to have a sovereign state was based on the demonstrable cultural continuity of the Jewish people since ancient times, on the argument that Israel was the "cradle" of the Jewish nation, and the fact that the Jewish nation has historically been a sovereign nation on this land before. But the claim to sovereignty itself is based on the right of a people to self-determination, not on genetic data or ancestry.
Some of Ostrer's misstatements will make Jewishly knowledgeable readers smile; his assertion that Sephardic Jews spoke "Latino" has real charm. (They spoke a Judeo-Spanish language called Ladino.) Other statements, like the false precision of asserting that "27,290 members of the kingdom of Israel" were deported by Assyria in 722 BCE, make it clear that Ostrer has no idea how to judge the reliability of historical sources. And no one familiar with European Jewish history or geography could describe a world in which Warsaw lies east of Kiev. Indeed, the proofreading of the book as a whole is abysmal.
Beyond unfamiliarity with the details of Jewish history, there is a quirkiness to the topics Ostrer chooses to discuss. He is, for example, fascinated by a minor early twentieth- century Jewish medical researcher named Maurice Fishberg who "proved" that Jews are not a race by the assiduous measurement of Jewish crania. But Ostrer fails to provide the context of the fin de siècle investigation of race and eugenics in which Jews figured in a minor way. He might have been better off with a coauthor better versed in Jewish and intellectual history.
A thornier problem is that Ostrer, like many research physicians, takes genetic data to be more scientific, and therefore more definitive, than they are. Genetically described populations reflect probabilistic clusters of markers inscribed in our DNA. They are not a concretization of race. Moreover, many of the conclusions that can be drawn from genetic evidence are reliant on the quality of accompanying historical data. For example, the Cohen modal haplotype is a cluster of distinctive genetic markers shared by a high percentage of contemporary Jewish Cohanim (the priestly clan that traces its ancestry back to Moses' brother Aaron). The idea that the ancestry that these men share can be traced to the ancient Israelite priesthood makes sense to almost everyone who views these data, but it is not inherent in the data. The data show only that these men share common ancestors who lived a specified number of generations ago. Estimating when those ancestors lived depends on an educated guess about the length of an average generation during the last 3000 years or so. But the idea that those ancestors were Cohanim is derived from our knowledge of Jewish history, it is not inscribed in the genetic markers.
Determining who does and who does not bear West Asian genetic markers is even more fraught. We do not have the genomes of the ancient Israelites, Phoenicians, Philistines or any of the other ancient peoples of the Near East. All that we have are genetic data on the peoples who live in the region today, and even these are not as refined as data for some other populations. We do know that there have been significant in-migrations, depopulation events, population bottlenecks, and constant contact with other peoples. What we do not know is the relative significance of these factors in producing modern Middle Eastern populations. The ongoing work on the genetic roots of the British, in which the influence of waves of conquest is beginning to be limned, is a possible model for the kind of investigation that could be done on the ancestral origins of the peoples of the Middle East. Meanwhile, Ostrer necessarily used a cruder tool, comparing his Jewish samples to modern populations of Druze, Bedouin and Palestinian Arabs. Although his findings show enough similarity to make shared origins for some ancestors among these four groups clear, there is work yet to be done.
This is important because there has been more than a little over-interpretation of the findings. For example, studies of the Y-haplotypes passed from father to son show that a remarkably high percentage of the male founders of Jewish communities in almost all parts of the diaspora were almost certainly descended from Near Eastern ancestors. This naturally roused curiosity about the mitochondrial DNA passed on by the founding mothers of diaspora communities; the findings support longstanding assumptions by historians that diaspora communities were often founded at least in part by Jewish men who reared Jewish families with local women who had not been born Jewish. A 2006 study of the mitochondrial DNA of Ashkenazi Jews excited particular interest because it demonstrated that as many as 70% of Ashkenazi (Eastern European) Jews descend from four women who lived about 2000 years ago. The authors of the study argue that "Near Eastern origin" of these four ancestors was "likely." Ostrer agrees that evidence shows "four common types of mitochondrial genomes... suggesting four founder females... (who) originated in the Middle East and their descendants migrated to Europe by way of the Rhineland." But the data do not trace a route along the Rhine-this is an assumption borrowed from historical evidence. Nor do the data make the ethnic or geographic origin of these four maternal ancestors of Ashkenazi Jews at all clear; merely, they raise the possibility, or arguably the probability, of a West Asian origin.
The greatest surprise has been the discovery of genetic evidence showing that Jews from the large communities of the diaspora-from Persia to Morocco, and from Basra to Vilna-are more closely related to one another in the male line than they are to the peoples among whom their ancestors lived for centuries. Harry Ostrer is surely correct when he writes, "To look over the genetics of Jewish groups and to see the history of the Diaspora woven in is truly a marvel."
What we have with advances in population genetics are new and marvelous tools with which to explore the past. Together with what we know from linguistics, history and archaeology, they can widen our understanding of the course of history, including the history of peoples and nations. But let's not get carried away, or carry our conclusions beyond the evidence.
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 conducts research on the ethical, legal and social implications of advances in genetics.
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