DNA USA

by Bryan Sykes

  The Y chromosome shared by the Cohanim effortlessly assumed the mantle of a “Jewish” gene, although of course it will have been drawn from the pool of Y chromosomes circulating in the Middle East at the time. Possession of Aaron’s Y chromosome does not prove descent from the brother of Moses, or that the bearer is Jewish. (This is like the familiar example of a fallacy: As all cats have four legs and all tables have four legs, therefore all cats are tables.) Many Christians and Muslims will also carry the same Y chromosome as Aaron, something worth noting in these troubled times. Indeed, since both Aaron and Muhammad were patrilineal descendants of Abraham, all direct male descendants of the prophet will be among them.

  While the patrilineal descent of the Cohanim is spectacularly consistent with biblical tradition, it is something of a special case because of its association with the rules of inheritance governing the priesthood. It does not mean that there will be a general genetic similarity between Ashkenazim that might underlie their sense of common ethnic identity. However, equally amazingly, it is there to be found. We have already seen the indirect evidence from the much higher incidence of Tay-Sachs disease among the Ashkenazim along with the suggestion that it may have conferred an evolutionary advantage on carriers. But even if that were the case, it would only come about if the Ashkenazim did not often intermarry with their non-Jewish neighbors and grew in numbers from a small founding population. At some point in their history the Ashkenazim must have experienced a “population bottleneck,” in the jargon of the professional geneticist.

  The evidence from Y chromosomes and from mitochondrial DNA shows this to have been the case. One indication is the variety of different Y chromosomes. Whereas all the main clusters are found among the Ashkenazim, a reflection of the large and diverse population of the Middle East from where they were originally drawn, their frequencies are quite different from the surrounding populations of Germany, Poland, and Russia. It is also important that the variety of different-detailed Y-chromosome signatures is also very much reduced in comparison with their non-Jewish compatriots. The same is true for mitochondrial DNA. All seven clans are there, but the frequencies are different. For example, roughly 8 percent of Europeans belong to the clan of Katrine, or haplogroup K, but among the Askenazim this rises to almost 40 percent. Within the Ashkenazi Katrines, as with their Y chromosomes, the number of distinct lineages is much lower than among Europeans in general. In fact, helped by complete mitochondrial sequencing, scientists have identified four founding mothers from whom 42 percent of all Ashkenazim are directly descended. Three are in the clan of Katrine and one in the clan of Naomi, or haplogroup N1, a very rare clan in Europe though commonly encountered in the Middle East. This is compelling evidence that European Jews have not homogenized with their European neighbors, and shows convincingly that the expansion of their numbers since the Middle Ages has been achieved by hereditary transmission rather than by conversion. The rule that a child born to a Jewish mother becomes a Jew appears to have been consistently followed. Compare European Christians, whose origins before the birth of Christ were exactly the same, where there is no inkling of any hereditary religious transmission, but plenty of vigorous, and often draconian, campaigns of conversion.

  American Ashkenazim share the same genetic features as their European and Middle Eastern ancestors, and the same desire to find out more about them and make the link as European Americans do in general. I have been involved in many cases, and they all share the features of genetic explorations by non-Jewish Americans searching for their roots. One recurring theme, though, is the confirmation—or refutation—of a genetic relationship to Europeans whose surname is not the same. It was very common for German and Russian immigrants to anglicize their surname when they registered at Ellis Island or one of the other entry points to the United States. “Bachmann” became “Beckman,” “Lehman” became “Lemmon,” “Gottlieb” became “Goodlove,” “Gutfreund” became “Goodfriend”, and so on. This was never a completely consistent process, so seeking a genetic link with potential relatives, both in the U.S. and in Europe, by looking for a Y-chromosome match has become very popular among American Jews. But perhaps the most unexpected application of modern genetics, again using Y chromosomes, comes not from the American Ashkenazim but from their cousins the Sephardim.

  Though Ashkenazi and Sephardic Jews share a common origin in Judaea, their paths through the Diaspora have been very different. While the Ashkenazim trace their European roots to central and eastern Europe, the Sephardim look to Spain and Portugal. Exactly how and when Jews began to arrive in the Iberian Peninsula is uncertain—it may have been as early as the incorporation of Hispania into the growing Roman Empire after the defeat of Carthage around 200 BC. The numbers grew with the Roman conquest of Judaea in AD 70 and the expulsions that followed the crushing of the Jewish revolts—the same dispersions experienced by the ancestors of the Ashkenazim. Until the adoption of Christianity by the Romans at the beginning of the fourth century, Jews in western Europe had largely avoided religious persecution, and even afterward the Christian church struggled to establish itself in the westernmost regions of the empire. The church’s influence in Iberia collapsed completely early in the fifth century following the barbarian invasions and the rule of the Visigoths, during which Jews enjoyed two welcome centuries of freedom from religious intolerance. This changed with the conversion of the Visigoth king, Recared, to Catholicism in AD 587, which was followed by a century of persecution and expulsions. The Muslim invasion of AD 711 was welcomed by Jews and ushered in a long period of tolerance and prosperity that led to its epithet as the “golden age” in Iberia. This period of religious freedom came to an abrupt end as fundamentalist North African Berbers took control at the end of the eleventh century. Many Jews left Spain altogether rather than face the choice of death or conversion to Islam.

  Gradually Spain and Portugal were brought back under Christian rule as cities and provinces were reconquered from the north. Although that rule was initially tolerant, the same religious fervor that energized the Crusades swept through the regained territories, and many Jews were killed. Things got steadily worse, and they faced the same dilemma as their cousins had to the south: conversion or death. Or if not death then humiliation and penury. Except that this time it was conversion to Christianity rather than Islam.

  The final stage began after the surrender of the last Muslim emirate of Granada to the Catholic monarchs Ferdinand and Isabella in January 1492. Despite promises of protection, by March of that same momentous year, Ferdinand and Isabella issued the “Edict of Expulsion” that compelled all Jews to leave Spain by the end of July. Estimates vary, but at least 150,000 are thought to have left. Most settled around the Mediterranean, while the fortunate ones reached the welcoming embrace of the Muslim Ottoman Empire, mainly around Istanbul and northern Greece, prompting the sultan to send a sarcastic message thanking Ferdinand for enriching his country by impoverishing Spain. On October 12 of the same year Columbus landed in the New World.

  Not all Jews left Spain and Portugal, where a similar conversion/expulsion order was issued in 1497. Those who remained chose conversion to Christianity, but often without a genuine religious realignment. While outwardly Catholic, many conversos, as they were known, continued to practice their true faith in secret. But they were not safe from the Spanish Inquisition, set up by the crown in 1478 to maintain strict adherence to Catholic orthodoxy and with the specific intention of ensuring that conversos remained converted. The Portuguese Inquisition followed in 1536, along even stricter lines. The courts set up by the Inquisition encouraged people to submit evidence against neighbors whom they suspected of continuing to practice Judaism. Even such indirect evidence as the lack of chimney smoke on Saturdays, indicating that the household was honoring the Jewish Sabbath, was used to root out heretics. The Inquisition routinely used torture to extract confessions. Those found guilty of heresy could confess, but those who refused were burned at the stake. By the time the reign of
terror was reaching its peak, the newly established Spanish and Portuguese colonies in the New World were seen by conversos as safe havens, free from the dangers of the Inquisition, and many left Iberia for Brazil, New Castille (now Peru), and New Spain—comprising Mexico and Spanish possessions in the Caribbean and what is now the southwestern United States. This was the beginning of the Sephardic settlements in America, predating by three hundred years the mass immigration of the Ashkenazim in the nineteenth and twentieth centuries. Many conversos felt safe enough to begin openly practicing their hidden faith, but this was only an interlude, and by 1569 both New Spain and New Castille had their own inquisitions.

  Genetically speaking, the Ashkenazic and Sephardic Jews are very different from each other, and this must be a reflection of their separate histories since the first Diaspora. The high frequency of Tay-Sachs disease, for example, is confined to the Ashkenazim. Though the Sephardim do suffer from several inherited disorders, including Tay-Sachs, these are no different in type or frequency to other Mediterranean peoples. For example thalassemia, the Mediterranean equivalent of sickle-cell disease that is caused by mutations in hemoglobin genes and offers a degree of protection to malarial infection, is found equally commonly in Sephardic Jews and non-Jews. Research using Y chromosomes also shows that, with the exception of the Cohanim chromosome, there is a much higher level of integration with adjacent European populations among the Sephardim than among the Ashkenazim. There is very little evidence in the Sephardim of the severe population bottlenecks that led to the current low level of Y-chromosome diversity among the Ashkenazim. The same is true of mitochondrial DNA, where there are no dramatic increases in the membership of any one clan compared to the Katrine effect among their Ashkenazim cousins.

  Nonetheless the connection between the Sephardic Jews of Iberia and their origins in the Middle East is still there. A recent study comparing Y chromosomes of self-identified Sephardic Jews living around the Mediterranean (and thus descended from exiled Iberians) with the modern population of Spain and Portugal showed a very high proportion of integration, with almost 20 percent of the Iberian population judged to be of Sephardic/Middle Eastern ancestry.3 However, as the authors explain, there are other possible reasons for this genetic correspondence, including the much earlier spread of agriculture from the Near East during the Neolithic period from about eight thousand years ago, and the maritime activities of Phoenicians from the eastern Mediterranean in the first millennium BC.

  Even allowing for this ambiguity, the discovery in America of Y chromosomes with a likely Sephardic origin has had an enormous and sometimes life-changing impact on the men who carry them. I found this out by talking to Bennett Greenspan, the president of Family Tree DNA, whom we first encountered in chapter 6. When I visited him in Houston he told me that several of his Hispanic customers from Mexico and the southwestern United States were initially amazed that their Y chromosomes turned out to be “Jewish.” Even though, as we have seen, this is an oversimplification, and no Y chromosome can be precisely defined as such, Greenspan assured me that in several cases this discovery awakened childhood memories of certain family customs that, until then, had no explanation—childhood memories like being told, “Never eat pork or you will die,” of Grandma lighting candles on a Friday night, of throwing out an egg if it contained a speck of blood, or of covering mirrors when somebody died. “Now it makes sense,” was a frequent response. These are the practices of observant Jews, and though the families were overtly Catholic, the Jewish traditions had lived on in secret. Genetics had revealed to these men that they were descendants of the conversos.

  Their ancestors certainly had a lot to fear from the activities of the Inquisition. Even political authority did not spare them, as in the chilling case of Luis de Carabajal, which Greenspan related. In 1579 this Portuguese adventurer and slave trader was appointed governor of a new province in northern Mexico, Nuevo León, bringing with him his wife, Doña Isabel, and their children. All was well until one day Luis heard his wife talking to the children in a strange tongue and, thinking she might be going mad, consulted with his priest. The priest realized that they were speaking Hebrew and reported this to the Inquisition. Doña Isabel was tortured until she confessed and implicated the whole family in these forbidden practices. They were all imprisoned. Luis de Carabajal himself, despite being the one who inadvertently exposed the heresy, died in prison. The others were not so lucky and were burned at the stake in Mexico City. The residual fear of these and similar horrors still lingers among the descendants of the conversos, and it takes time for men who discover their genetic link to come to terms with the news. But when they do, Greenspan told me, several have taken the plunge and formally converted to Judaism.

  Though the Sephardic and Ashkenazi Jews living in the United States today have very different histories and very different reasons for coming to America, their reaction to genetic research is in stark contrast to that of Native Americans, as the case involving the Havasupai Indians and the University of Arizona testifies. While Native Americans, as we shall see, generally regard genetics with extreme suspicion, American Jews have been at the forefront of genetic research. Bennett Greenspan is a good example. Himself an Ashkenazi Jew, the company that he founded was supported by the Jewish community in Texas right from the start. Indeed, as he explained to me, he deliberately sought their reaction even before he launched it in 2000, figuring that their traditional intelligent cynicism would highlight any potentially costly flaws in his business plan. While the very practical benefits accruing from Tay-Sachs research have virtually eliminated the disease among American Jews, there must be another element to account for the difference between the Native American and Jewish reactions to genetics. While both have reason to fear racial discrimination and the ever-present threat of eugenics, their reactions are poles apart. The main difference, as I see it, is that while Native Americans have been on the receiving end of gung-ho and invasive academic projects run by other people, Jewish Americans have looked into their genetics themselves.

  9

  The Africans

  Cape Coast Castle, Ghana.

  The last continental group to converge on America was the one with the planet’s deepest ancestral roots, for it was in Africa about two hundred thousand years ago that our species Homo sapiens first emerged from among the several other contemporary hominids. They, too, had evolved from earlier forms, moving further and further away at each step from their more apelike antecedents. The hominid line, of which we are currently the only known survivor, converges with the common ancestor we share with our closest animal relative, the chimpanzee, about six million years ago. Some of our early ancestors, notably the very sturdy Homo erectus, left Africa at least two million years ago and spread across Europe and Asia, though not—as far as we know—to America. Some one hundred thousand years ago, a few Homo sapiens ventured beyond the continent of their ancestors to settle in Asia and in Europe. Slowly they replaced other hominids, like the Neanderthals, so that by thirty thousand years ago they had a virtual monopoly. Small pockets of related species lived on for a few thousand years in remote locations, like the Indonesian island of Flores, and the Altay Shan mountains of Siberia. Even now, regular though always inconclusive reports emerge from distant lands of strange semihuman creatures that are said to be the last survivors of other hominid species. Sasquatch and Bigfoot in the dense Pacific Northwest forests, the yeti of Nepal and the migoi of Bhutan in the Himalayas, and the almasty of the Caucusus Mountains. In the past I have investigated scraps of skin and hair from some of these without, yet, finding any convincing DNA proof of the legends. But that is another story. For the purpose of DNA USA, we can take it that humans evolved in Africa and spread from there to the rest of the world. So to say that we are all Africans has a literal truth even if it has become a rather tired aphorism.

  Most African Americans, as is universally known, came to America as slaves. But they were not by any means the first Africans to leave
the continent in historical times. Africans have, contrary to common belief, been coming to Europe for thousands of years. They were, for example, prominent members of the Roman occupation force in Britain after the invasion of AD 43. The troublesome Scots and Welsh “insurgents” soaked up Roman military resources, and by the second century it has been estimated that there were nearly three hundred thousand auxiliary troops in Britain, of which between 10 and 25 percent were Africans. This proportion grew during the British campaigns of the Roman emperor Septimius Severus in the early second century AD. He had a Roman mother and a Libyan father, though there is no compelling likeness of him as black. Black African soldiers also feature on Trajan’s Column in Rome, the richly carved celebration of the eponymous emperor’s victorious military campaigns erected in AD 155. Interestingly, the Africans are wearing their hair in dreadlocks.

  Although intermarriage between the occupying forces and indigenous British women was not permitted by Roman law until AD 197, this only legalized what had been going on since the early days. At the end of their twenty-five years of military service, auxiliaries were given land and a pension, and many chose to remain close to their garrison with their families rather than return home. Some would have been African auxiliaries. The Vikings, who dominated large parts of Britain from the eighth to the fifteenth centuries AD, certainly brought Africans as captives to Dublin, Ireland, and Orkney, off the north coast of Scotland. Black Africans also feature in British mythology, especially in the legends of King Arthur and the Knights of the Round Table. Sir Palamedes, the original Dark Knight, was black. Although King Arthur was largely an invention of the twelfth-century Welsh cleric Geoffrey of Monmouth, his imaginative History of the Kings of England showed, if nothing else, that black Africans were no strangers to Britain and the rest of medieval Europe. These records contradict the later notion that, to Europeans, Africa was terra incognita, the unknown and unknowable land, the “Dark Continent,” the last refuge of Kurtz in Joseph Conrad’s Heart of Darkness. The discontinuity with past knowledge is summed up by the casual remark to me by the Dartmouth professor of English Gretchen Gerzina. Searching in a well-known London bookshop for a history of black people in Britain she was met with the sharp response from the saleswoman, “Madam, there were no black people in England before 1945.”1