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Is There a Jewish Gene?

lewontin_1-120612.jpg
Palazzo Patriarchale, Udine/De Agostini Picture Library/Bridgeman Art Library
Giovanni Battista Tiepolo: The Sacrifice of Isaac (detail), 1726–1739

The question of ancestry has been of human concern in virtually all cultures and over all times of which we have any knowledge. Whether it be a story about the origin of a particular tribe or nation and its subsequent mixture with other groups, or curiosity about a family history, there is always the implication that we understand ourselves better if we know our ancestors and that we, within ourselves, reflect properties that have come to us by an unbroken line from past generations. As treasurer of the Marlboro Historical Society in Vermont, I am the recipient of requests for printed copies of the Reverend Ephraim Newton’s mid-eighteenth-century history of our town, 70 percent of whose pages consist of “Genealogical and Biographical Notes” and a “Catalog of Literary Men.” Over and over our correspondents write of the “pride” they have in descending from these early settlers.

Surely pride or shame are appropriate sentiments for actions for which we ourselves are in some way responsible. Why, then, do we feel pride (or shame) for the actions of others over whom we can have had no influence? Do we, in this way, achieve a false modesty or relieve ourselves of the burdens of our own behavior? As a descendant of late-nineteenth-century Eastern European immigrants I cannot depend on Reverend Newton’s pages to explain my frequent contributions to The New York Review, but neither have the extensive “begats” in Genesis 10 or Matthew 1 been more enlightening.

My own skepticism notwithstanding, the belief is widespread that knowledge about the personal characteristics of ancestors who have never directly entered into our lives is relevant to our own formation. Moreover, that relevance is seen not simply as arising from our conscious knowledge about those ancestors, but from a deeper source, our genetical inheritance, which also would operate to form us in part, irrespective of our consciousness of the past. That belief is summed up in the title of Harry Ostrer’s book, Legacy: A Genetic History of the Jewish People. It is also implied in the title of a book by Raphael Falk, Zionism and the Biology of the Jews, whose English translation from the Hebrew original has yet to appear.1 While the term “race” is not used explicitly in these titles, in large part because the term is so loaded, there is considerable discussion of the Jews as a race or, using a less charged word, as a “people.”

“Race” is a term of uncertain etymology and many meanings. It may refer to a whole species (the “human race”), a collection of loosely related individuals with a common appearance (the “white race”), a nation (the “race of Englishmen”), or a single family (“he was the last of his race”). Compounding the ambiguity is the substitution of “people” or “tribe” that seems to shed the historical fardels with which “race” is burdened. Are the Navajo a tribe, a people, or even a race? In a former time, when the classification of humans depended on manifest physical features like skin color, facial and hair form, and skull shape, members of a “race” as opposed to a “people” were claimed to be recognizable as such by the external physical features common to all individuals of the same “race.”

In all these usages the implication is one of common ancestry tracing back ultimately to some relevant founding group, but obviously all such ancestries must incorporate members of other groups at various times in their histories. Even Cain managed to find a wife in the Land of Nod or else he married his sister. For the German National Socialists, having more than two Jewish grandparents was sufficient to define a Jew. But if every defined human group necessarily has, at any moment in its history, some ancestry from a variety of other collections of humans, how are we to delineate those groups and reconstruct their family histories?

Ordinary genetics is not sufficient. Each of us has one copy of our chromosomes from our mother and one copy from our father. But of the chromosomes I got from my mother, half of those came from her mother and half from her father so, roughly speaking, I resemble my maternal grandmother only in a quarter of my genes. It doesn’t take many generations before I resemble a particular remote great-grandparent in a very small fraction of my genes. If one of my ancestors four generations ago were black, there is a good chance I would have inherited none of her pigment genes or so few that they would not be apparent in my own skin color.

This random inheritance of genes makes it very difficult to reconstruct the variety of ancestors in remote past generations. Fortunately for those interested in the reconstruction of ancestry there are two useful exceptions to the rule that we inherit only a random one of the two sets of genetic information possessed by each of our parents. One of those exceptions is the single Y chromosome carried by males but not by females. The Y chromosome carries very few genes. We know this to be true because, very rarely, an individual is born having received, as usual, one X chromosome from the female parent but, abnormally, neither an additional X chromosome nor a Y chromosome from the male parent. This individual, called an “XO” type, is a sterile female but otherwise is normal. This general normality in the face of having only a single X chromosome but no Y chromosome tells us that the usual effect of a Y chromosome is essentially only to cause a switch from female to male development.

As a consequence, variation among Y chromosomes can be used to reconstruct ancestry without the confounding effect of possible natural selection for one or another variant. Every son inherits his father’s Y chromosome, which was passed, intact, through the sequence of male ancestors to the present generation. Thus, by examining the Y chromosome DNA from a group of males in some generation and comparing it to the Y chromosomes of various other populations, we can reconstruct the contribution of males from various sources in previous generations to the present population. In particular we can ask what proportion of the Y chromosomes in a given population came from some particular group of historical interest. For example, we can estimate how much Arab slave traders contributed genetically to the present black populations of southeast Africa if the Y chromosomes of the Arabs contain characteristic DNA sequences that are rare or absent elsewhere, but in unusually high frequency among the present African inhabitants of Tanzania.

The other exception to random inheritance is not in the chromosomes, but in the DNA of cellular organelles called mitochondria. Although the cells of both sexes generally contain mitochondria, these organelles are excluded from the bodies of mature sperm and so are never passed into the fertilized egg, which has its own maternally derived mitochondria. Our mitochondria, then, provide us, both male and female, with a record of our maternal ancestry, uncontaminated by their male partners.

Harry Ostrer, who is a professor of genetics at Albert Einstein College of Medicine, and Raphael Falk, who is one of Israel’s most prominent geneticists, depend heavily on our ability to trace ancestry by looking at the DNA of Y chromosomes and ribosomes. Their books are responses to the widespread desire to trace that ancestry and to describe the degree to which the world’s present distribution of Jews consists, with a few possible exceptions like the Kaifeng Jews of China, of people with ancient common roots. For Falk, as the child of German Jews threatened with the Final Solution, the longing for Zion was expressed, as in his parents’ case, “primarily as a wish for relief from the persecutions and other hardships of Jewish life in the Diaspora.” For Ostrer, on the other hand, as he writes in his preface:

Having a 3000-year genetic legacy can be a source of group identity and pride in the same way that having a shared history, culture, and religion can be sources of pride.

Once again we have the question of why having knowledge of remote ancestors and a shared history makes us “proud.” Is it that preening ourselves before the glass of history seems less egotistical than inspecting our images in the glass of fashion?

The difference between the motivations of the authors is manifest in the properties each assigns to heredity. The element of “pride of ancestry” that permeates Ostrer’s text leads him, especially in his chapter on “Traits,” to extensive discussions of intellectual and professional accomplishment and the degree to which they may reflect innate biological capacity. While he can hardly be described as a naive biological determinist, it seems clear that he leans in the direction of attributing some importance to the biology of the Jews in forming their social accomplishments. He asserts that

accidents of birth, wealth, privilege, and education are not sufficient to explain who will become outstanding lawyers or physicists.

Nevertheless, Ostrer does not offer any evidence that the intellectual qualities that make so many Jews into lawyers and physicists are a consequence of their genetic superiority. Indeed, we know nothing about the genetics of nonpathological variation in the cognitive capacities of the brain. An attempt to determine whether intellectual life is genetically heritable would require a large adoption study in which infants would be reared in a controlled environment in circumstances that prevented their caretakers from knowing their family or social origins. Moreover, given the sensitivity of central nervous system development to nutritional and other external factors, the study would have to begin with newborn infants and we would still miss the effects of prenatal circumstances. We should not be surprised that such a study has not been done.

Ostrer’s view of the causes of the high frequency of intellectual careers among Jews is purely speculative. After more than a century of claims that high intellectual or artistic accomplishment is somehow rooted in heredity and, more specifically, in the possession of “genes for high intelligence” or “genes for creativity,” there is no credible evidence for their existence. Indeed, the search for genetic superiority has largely given way to an extensive effort to find the genetic basis for a host of physiological debilities. There is a certain irony in claiming an undemonstrated biological superiority for a group, six million of whom were slaughtered for their claimed natural degeneracy.

Despite this interest in the social and intellectual characteristics of Jews, to which he devotes about a fifth of his text, Ostrer’s chief concern is with the history of the Jews, as revealed in their actually known genetic similarities to and differences from other populations. These similarities and differences occur thanks to various proportions of alternative genetic forms rather than being absolute differences between populations. There is no known “Jewish gene,” and the same comments I have made about the evidence concerning genes for “high intelligence” and “creativity” apply to the existence of those properties in alternative genetic forms.

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Louvre, Paris/RMN-Grand Palais/Gérard Blot/Art Resource
‘Jews in a Synagogue’; etching by Rembrandt

As an Israeli, Falk’s motivation is directly connected to the political issue of Zionism and the claim of Jews for a national state:

In this book I wish to discuss two issues: the claim that there is a biology of the Jews on the one hand, and the attempts to integrate this claim into a consistent history of national-political Zionism, on the other hand.

For him the biology of the Jews enters not as a determinant of their cognitive abilities but as a tool for defining the Jews as a collection of related people who can lay a claim to a geopolitical existence, and for attempting a reconstruction of their history:

In the present world of scientific-technocratic reasoning, biological research is a major tool that demonstrates and validates links between present-day Jews and the land that for centuries has been, unequivocally, the glue of their socio-cultural bonds.

An example of the ultimate irony of personal history is that the author of The Genealogical Science, which deals with the immense complexity of Jewish ancestry, is the occasionally church-attending daughter of a Protestant mother of Northern European ancestry and a father whose name, Abu El-Haj, tells us that a forebear made the pilgrimage to Mecca.

Nadia Abu El-Haj’s avowed purpose is to make clear “the ways in which ‘the past’ is understood to be a constitutive element of the self.” The key word here is “understood.” Her emphasis, over and over, is on how the knowledge of ancestry, revealed by modern techniques of genetics, may serve as a basis for and a legitimation of a self-image. For her, to ignore the genetic information about ancestry “is to abandon a historically authentic self that I carry around within.”

Once again, as in works on the genetics of race, we encounter the concept of an “authentic” self that lies hidden and unexpressed, but which in some sense is the essence of what I am, even if unperceived and without a basis in any scientific demonstration. The concept of a self that is an authentic essence, but not clearly perceived, suggests that my manifest properties and attitudes are a mere patina and that, in ways that I do not recognize, my inherited inner self is struggling to assert itself. The Austrian Catholic Mendel and the Austrian Jew Freud meet on the speculative ground of our inner being.

None of the books being considered claims that there are genetic elements that are characteristic of all or even a large majority of Jews. The closest thing to a “Jewish gene” is an element on the Y chromosome of males that has been passed down at least for several millenia in the male line of the Cohanim family, and whose presence in a man’s genome is evidence of descent from the priestly class. The frequency of this “CMH” (Cohanim Modal Haplotype) is around 50 percent among the members of the Cohen line. This haplotype is by no means exclusive to the Jews. It is found in some other Middle Eastern groups in frequencies of around 20 percent. More unexpected is the very high frequency of the CMH type among the Lemba of southern Africa. These black Africans also have a culture that excludes the eating of pork and the mixing of milk and meat, and includes the circumcision of male children. They claim descent from migrants from the region of what is now Yemen. However, it seems more likely, as Ostrer also concludes, that it was, in fact, the Arab slave traders who spread this culture as Islamic tradition.

In Henry M. Stanley’s account of his passage through southeastern Africa from the region of Dar es Salaam in search of Livingstone, he tells of following the old Arab slavers’ routes through village after village in which the chief was referred to by the title “Sheikh.” Moreover, in a practice very different from the Jewish one, male circumcision among the Lemba occurs not in early infancy but around the age of eight, a practice characterisic of Muslim groups. If one takes account not only of the CMH but of all the genetic variation known on the Y chromosome, the Lemba fall halfway between other sub-Saharan Africans and the populations of the Middle East.

The same kind of questions that are asked about the chain of male ancestry by looking at our Y chromosomes can be investigated in both men and women by studying the mitochondrial DNA we have derived in an unbroken chain from our line of female progenitors.* It turns out that there is much more variation in the mitochondrial DNA of Jewish women than in the Y chromosomal DNA of Jewish men. This is understood by Falk and Ostrer to mean that when the Jews fled ancient Palestine to found the Diaspora, it was not whole families that fled but largely the men, who then found new local mates in the places to which they migrated. Thus, most of the mothers of these founding communities were not themselves Jews but were sources of new genetic variation, and the present genetic variation among Jews is consequently much greater than it was in Palestine three millennia ago.

Y chromosomal DNA or mitochondrial DNA is used by anthropologists and historians precisely because they are each passed down intact from parent to child through the line of parents of one sex unmixed by the genetic information about the parents of the other sex. But what is, on one hand, an advantage for historical information about an ancestor in the remote past is devoid of information about subsequent history, a history that may dominate the present. To satisfy the curiosity of a former student of mine, now the director of the National Geographic Society’s project to reconstruct the history of human migrations using patterns of present human genetic variation, I let him determine that I carry the CMH Y chromosome. Thus, my son, James, also carries it, as does his son. But my wife is of Scandinavian/English ancestry and my son’s wife is of similar stock so, although my grandson must also carry the CMH Y chromosome, his X chromosome is Northern European, as is, given my ignorance of my own distant ancestry, at least three quarters of the rest of his genome. Even the Nuremberg Laws would have exempted him from what would have been my own fate.

Why, then, should he, like most people, be interested in his ancestors? What is the logic of family pride or family shame? He may simply be curious, as so many are.

Abu El-Haj, perhaps because of her own mixed ancestry, has a very sophisticated view of the motivations for and consequences of investigating one’s origins. She argues that the molecular evidence “generates, grounds, and authenticates…narratives of origins, kinship, and history” but its purpose is not to claim that any particular human nature flows from those origins. Rather, she sees such evidence as a manifestation of her belief that the consciousness of being a member of any genetically related ethnic group somehow tells us something fundamental about who we really are, about the solution to our quest for self-knowledge, and

requires that one actively embrace that “ancestry,” that one learn about and fashion oneself according to its cultural or religious principles, thereby transforming ancestry into identity or selfhood.

While this belief in the fundamental importance of a knowledge of ancestral origins is undoubtedly widespread, it is far from universal. Yet an indifference to ancestry is sometimes taken as a rejection of one’s “real” identity, even of “self-hatred.” It seems clear that while one may see oneself as “embracing” one’s ancestry, one may also be indifferent to such ancestry, or reject it. No one, including Abu El-Haj, claims that the genetic facts by themselves exert a force obliging people to take one conscious position or another.

Abu El-Haj was at the center of an academic controversy that arose from her first book, Facts on the Ground: Archaeological Practice and Territorial Self-Fashioning in Israeli Society, which appeared in 2001, a year before she became a nontenured member of the faculty in the Department of Anthropology at Barnard, followed several years later by her additional appointment as director of graduate studies at Columbia’s Department of Anthropology. However, when she was being considered for promotion to a tenured professorship in 2007, a bitter struggle over her scholarship was induced by a widely circulated petition claiming that Facts on the Ground was a dishonest, inferior, and biased work that knowingly misrepresented the quality and content of archaeological work on ancient sites in Israel.

The originator of the petition was a graduate of Barnard, Paula Stern, who had emigrated to Israel,2 but her campaign against El-Haj developed considerable support among Barnard and Columbia alumni and some faculty members, as well as a number of writers, political activists, and academic supporters of Israel both inside and outside of Columbia. In the end the campaign against Abu El-Haj failed to prevent her promotion to a tenured position in 2007.

The last chapter of The Genealogical Science considers “the implications of treating DNA as ‘a history book’ for our understandings of both ‘history’ and of its relationship to the self.” For Abu El-Haj, genetic history is an example of a general belief in the “importance and knowability of the past” because, for her, “fundamental aspects of who one is are determined by one’s past” and moreover one can know and reconstruct the past on the basis of remainders of that past, including genetic mutations.

Thus, there is a “fundamental continuity between race science and anthropological genetics” and a belief that “who we really are collectively and individually is given by and legible in biological data.” But she ends by insisting, as in the conclusion about something like embracing “one’s ancestry,” earlier stated, that

the choice to learn about myself, to remain who I am or to realign my sense of self vis-à-vis new revealed bodily facts about who I have always already been, remains mine to make.

What is revealed here in her reference to “bodily facts about who I have always already been” is an underlying biological determinism that seems to make her present persona a cosmetic, deliberately applied to the face of an underlying “authentic self.” What is not revealed in her book is what she regards as the nature of that self.

Letters

Distressed Genes: An Exchange January 10, 2013

  1. *

    The version of this article published in the Review ’s December 6 issue contained several errors in my references to the use of RNA found in ribosomes and mitochondria to trace female ancestral lines. The standard method at present is to use so-called mitochondrial DNA, as the mitochondria are essentially excluded from the mature sperm and are thus inherited only through the female line. The text above has been revised to reflect this. 

  2. 1

    Zionut Vehabiologia Shel Hayehudim (Tel Aviv: Resling, 2006). 

  3. 2

    A detailed history of the campaign against El-Haj’s promotion can be found in Jane Kramer, “The Petition,” The New Yorker, April 14, 2008. 

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