The Jewish Story and a Reassessment of the Dna Evidence
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Journal of Genetic Genealogy 1:12-33, 2005 A MOSAIC OF PEOPLE: THE JEWISH STORY AND A REASSESSMENT OF THE DNA EVIDENCE Ellen Levy-Coffman The Jewish community has been the focus of extensive genetic study over the past decade in an attempt to better understand the origins of this group. In particular, those descended from Northwestern and Eastern European Jewish groups, known as “Ashkenazim,” have been the subject of numerous DNA studies examining both the Y chromosome and mitochondrial genetic evidence. The focus of the present study is to analyze and reassess Ashkenazi results obtained by DNA researchers and synthesize them into a coherent picture of Jewish genetics, interweaving historical evidence in order to obtain a more accurate depiction of the complex genetic history of this group. Many of the DNA studies on Ashkenazim fail to adequately address the complexity of the genetic evidence, in particular, the significant genetic contribution of European and Central Asian peoples in the makeup of the contemporary Ashkenazi population. One important contribution to Ashkenazi DNA appears to have originated with the Khazars, an ancient people of probable Central Asian stock that lived in southern Russia during the 8th-12th centuries CE. Significant inflow of genes from European host populations over the centuries is also supported by the DNA evidence. The present study analyzes not only the Middle Eastern component of Ashkenazi ancestry, but also the genetic contribution from European and Central Asian sources that appear to have had an important impact on Ashkenazi ancestry. Introduction Early on, the unique history of the Jews attracted The word “Jew” has a mosaic of meanings: it DNA researchers who sought to solve the mystery defines a follower of the Jewish faith, a person who of the origins of the Jewish people. Researchers had has at least one Jewish parent, or a member of a previously relied on linguistic, anthropological and particular ethnic group (“Jewish”). There are many archaeological evidence to try to address this Jews who do not practice Judaism as a religion but question; genetic genealogical research has opened define themselves as “Jewish” by virtue of their up a new area for researchers to explore. family’s heritage and identification with the culture and history of the Jewish people. One question the DNA studies sought to answer was whether the genetic ancestry of contemporary Thus, Judaism is a mosaic of culture, religion, Jewish populations demonstrated, to any degree, ethnicity, and for some, a way of life. It is an their supposed descent from the ancient Israelites of identity that is not quite a nationality, but neither is the Middle East of three thousand years ago. Or it a simple ethnic or cultural phenomenon either. rather, did the DNA evidence indicate that Jews This unusual combination of characteristics, were simply a people who came into being in coupled with Jewish resistance over the centuries to Europe during the Diaspora years, being mainly assimilation and strong adherence to their religious comprised of those descended from European faith, has contributed to the intense feelings of ancestors? Or, as some historical researchers curiosity, hatred, admiration, attraction and suggested, did the DNA of Jews mainly reflect hostility by the rest of the world. ancestry from the Khazars, an ancient tribal people with roots in both Central Asia and Russia who th converted to Judaism in the 8 century? This paper represents a new examination and reassessment of the Jewish DNA studies to date, Received: February 15, 2005 presenting possible alternative explanations for the origins and distribution of certain genetic markers Address for correspondence: Ellen Coffman, among Jewish populations, and in particular, among [email protected] the group of Jews known as “Ashkenazim.” 12 Coffman: A Mosiac of People: The Jewish Story and a Reassessment of the DNA Evidence 13 Recent genetic research has greatly expanded our Examination of mitochondrial DNA, on the other understanding of the probable origins and distinct hand, is based on the combined polymorphisms of geographic patterns of certain groups of people, the control region (hypervariable segments I and II, including Jews. This recent research has superceded or HVSI and HVSII) along with specific SNPs in the some of the earlier studies on Jewish DNA, allowing coding regions of DNA found in the mitochondria. a reassessment of the theories of Jewish origins in Both males and females have mtDNA, which they light of this new research. have inherited from their mothers, whereas Y chromosome DNA is found only in males and is The new analysis shows that Jewish ancestry reflects inherited directly from their fathers. a mosaic of genetic sources. While earlier studies focused on the Middle Eastern component of Jewish Like the Y chromosome data, mtDNA sequences are DNA, new research has revealed that both sorted into major phylogenetic haplogroups as well. Europeans and Central Asians also made significant Recent analysis on both mtDNA and Y genetic contributions to Jewish ancestry. Moreover, chromosome SNPs have allowed researchers to while the DNA studies have confirmed the close further divide many haplogroups into sub-branches, genetic interrelatedness of many Jewish communities, known in the DNA literature as “sub-clades.” The they have also confirmed what many suspected all geographic distribution of mtDNA haplogroups and along: Jews do not constitute a single group distinct their sub-clades also adds to our understanding of from all others. Rather, modern Jews exhibit a relationships of groups of people, including Jewish diversity of genetic profiles, some reflective of their populations. Semitic/Mediterranean ancestry, but others suggesting an origin in European and Central Asian groups. The blending of European, Semitic, Central The Birth of European Judaism Asian and Mediterranean heritage over the centuries has led to today’s Jewish populations. This section is intended to provide the reader with a brief history of the Jews in Europe as well as define In examining Y chromosomal diversity in this terms used frequently in the Jewish DNA studies, review, two types of data are considered: Single such as “Diaspora,” “Sephardim,” and Nucleotide Polymorphisms (SNPs), and Short “Ashkenazim.” Furthermore, since Jews appear to Tandem Repeat Loci (STRs). STR markers are have both Israelite/Middle Eastern and European characterized by mutation rates much higher than genetic ancestry, an understanding of the Jewish those seen with SNPs. SNPs, on the other hand, are experience in Europe is important in explaining how derived from rare nucleotide changes along the Y European ancestry became an integral part of the chromosome, so-called unique event polymorphisms Jewish genetic makeup. However, this section is not (UEP). These UEPs represent a single historical intended to be an extensive recounting of the history mutational event, occurring only once in the course of the Ashkenazi people. of human evolution. UEPs have been given a unified nomenclature system by the Y Chromosome The birth of European Judaism begins with the Consortium (2002), resulting in the identification of Diaspora. “Diaspora” is a term derived from the each UEP with a particular haplogroup. Greek work meaning “scattering.” While the word was originally used by ancient peoples to identify While I examine both types of Y chromosome data, any group that was exiled or resettled from their I rely primarily on SNP data due to its increasing homeland, the term has now become particularly use by researchers as a tool in reconstructing the associated with the Jewish exile from ancient Israel peopling of the world. Research on the diversity and resettlement elsewhere. and geographic patterns of haplogroups have provided researchers with a greatly expanded The Jews resettled in many distant lands, even as far understanding of prehistoric movements of people as China. This work, however, focuses specifically and a means of better understanding the present-day on the Ashkenazi Jewish experience. Jews were genetic variation among populations. Research with subdivided into groups depending on where they STR “haplotypes” is also occasionally discussed in resettled. Ashkenazi Jews are the Jews of France, this paper, particularly in light of its ability to Germany, and Eastern Europe. Sephardic Jews are demonstrate a high rate of endogamy, genetic drift, the Jews of Spain, Portugal and North Africa. and founder effects among Jewish populations. Mizrachi/Oriental Jews are the Jews of the Middle East. Certain Jewish communities do not fit into 14 Journal of Genetic Genealogy, 1:12-33, 2005 these distinctive groupings – in particular, the The Israelite Kingdom arose in the 11th century BCE Falasha Jews of Ethiopia and the Chinese Jews. in an area between modern-day Lebanon, Jordan and Saudi Arabia. Current archaeological evidence Contemporary Jewry is comprised of approximately indicates that the Israelite kingdom arose out of the 13 million people, of whom 5.7 million live in the earlier, Bronze Age Canaanite culture of that region, United States, 4.7 million live in Israel, and the and displayed significant continuity with the remainder resides throughout the world (Ostrer Canaanites in culture, technology, language and 2001). Approximately 90% of the Jews of the U.S. ethnicity (Dever 2003, pp. 153-154). are of Ashkenazi origin, while among the Jews of Israel, 47% are Ashkenazi, 30% are Sephardic, and While the Canaanites were a Western Semitic people 23% are of Mizrachi/Oriental origin (Ostrer 2001). indigenous to the area, they appear to have Within Jewish groups, membership in three male consisted of a diverse ethno-cultural mix from the castes (Cohen, Levi, and Israelite) is determined by earliest times. It is from this diverse group that the paternal descent (Behar et al. 2003). evolution of the Israelites occurred. Although little is known about these groups, they probably The history and genetic ancestry of Sephardic Jews included some of the following populations: is dealt with in only a cursory fashion here.