The population genetics of the Jewish people

Authors: Harry Ostrer Karl Skorecki

Publish Date: 2012/10/10

Volume: 132, Issue: 2, Pages: 119-127

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Abstract

Adherents to the Jewish faith have resided in numerous geographic locations over the course of three millennia Progressively more detailed population genetic analysis carried out independently by multiple research groups over the past two decades has revealed a pattern for the population genetic architecture of contemporary Jews descendant from globally dispersed Diaspora communities This pattern is consistent with a major but variable component of shared Near East ancestry together with variable degrees of admixture and introgression from the corresponding host Diaspora populations By combining analysis of monoallelic markers with recent genomewide variation analysis of simple tandem repeats copy number variations and singlenucleotide polymorphisms at high density it has been possible to determine the relative contribution of sexspecific migration and introgression to map founder events and to suggest demographic histories corresponding to western and eastern Diaspora migrations as well as subsequent microevolutionary events These patterns have been congruous with the inferences of many but not of all historians using more traditional tools such as archeology archival records linguistics comparative analysis of religious narrative liturgy and practices Importantly the population genetic architecture of Jews helps to explain the observed patterns of health and diseaserelevant mutations and phenotypes which continue to be carefully studied and catalogued and represent an important resource for human medical genetics research The current review attempts to provide a succinct update of the more recent developments in a historical and human health contextSince their emergence as a national and religious group in the Middle East over 2000 years ago Biran and Naveh 1993 Jews have maintained continuous cultural and religious traditions amid a series of Diasporas BenSasson 1976 Along the way others were converted into the Jewish fold The origins and relatedness of the various Jewish groups have been much speculated upon over the past century Jews have described themselves as a “people” based on their shared religion without a clear indication of the genetic lines of descent since their early history Albert Einstein captured this uncertainty when he wrote to the Berlin rabbis in 1921 “I notice that the word Jew is ambiguous in that it refers 1 to nationality and origin 2 to the faith” Einstein et al 1987With the advent of modern population genetics based on analysis of genetic markers in the second half of the twentieth century investigators have attempted to categorize the origins and relatedness of Jewish people Because relatively few polymorphic markers were available at first the early studies focused on genetic distances between groups and established hierarchies based on these distances BonneTamir et al 1978a b 1977 Carmelli and CavalliSforza 1979 Karlin et al 1979 Kobyliansky et al 1982 Livshits et al 1991 Population genetics has been enhanced by the identification of millions of polymorphic markers that reside in close proximity to one another along the genome and that vary in their allele frequencies among populations These discoveries have led to greater precision for estimates of genetic distances These discoveries have also led to new types of analyses that were not available in the past The analyses have included deconvolution of ancestry for whole genomes or for segments of individual genomes and analysis of segmental sharing among individuals that provide greater accuracy for estimating their degree of relatedness Atzmon et al 2010 Bryc et al 2010At the same time genetic analyses of diseases have continued in Jewish populations These have included diseases with a clear Mendelian basis rare syndromes often identified first in a single family common conditions that are more prevalent in Jewish populations and common conditions for which the complexity might be simplified by studying Jewish populations Interest in studying these disorders has accelerated with the advent of genomic sequencebased personalized medicine research Ostrer 2011 Here we provide a description of the population genetics of the Jewish people based on these recent discoveries and a progress report on the genetic basis of diseasesThe history of the Jewish people from Classical Antiquity onward provides a guide to understanding their population genetics and is most accurately recorded beginning at the time of the Greek and Roman Empires Up to 6 million Jews are thought to have resided in the Roman Empire comprising 10  of the total population Fishberg 1911 In the period immediately preceding the fall of the Second Temple in 70 CE adherents to Judaism were located throughout the Roman Empire to the west and extended into the Arsacid Empire in the east Isaac 1998 These Jews are likely to have been the ancestors of the subsequent Jewish Diaspora populations that lived in the Middle East “Mizrahi” Europe “Ashkenazi and Sephardic” and North Africa Baron 1952 The number of adherents to Judaism residing outside of the Kingdom of Judea is thought to have greatly exceeded those residing within Judea with the largest communities in Alexandria in Egypt and Antioch in contemporary Turkey Evidence for these communities remains in the archeological record such as the wellstudied community in DuraEuropos then at the boundary of the Roman Empire and now in presentday Syria Chi et al 2011 Most introgression with nonJews occurred during times of relative liberalism and tolerance including the Hasmonean period in Classical Antiquity 140–37 BCE and modern times Shanks 1988 Introgression between Jewish groups also occurred following the Spanish Inquisition when Sephardic Jews left the Iberian Peninsula 1492–96 CE and migrated to Italy the Balkans Syria Morocco and Algeria often settling within existing Jewish communities Stillman 1991 Although not sustaining communities that were recognizably Jewish Sephardic Jews also migrated to the New World and contributed to the formation of contemporary Hispanic and Latino nonJewish populations Hordes 2005 Since the fall of the Second Temple and the end of the Judean kingdom in 70 CE religious law and antiSemitism in the emerging Christian and Islamic worlds favored marrying within the Jewish fold Cohen 1999 Goldstein and Evans 2012 Wistrich 2010Judaism was also brought outside the Roman Empire to Yemen Ethiopia India and China Many of these communities were longstanding and were observed by Benjamin of Tudela during his travels of the twelfth century Benjamin 1983 The origins of these communities have been the subject of considerable speculation Some communities have been thought to be the descendants of the Lost Tribes that were forced into Assyrian exile following the destruction of the Kingdom of Israel in 622 BCE although unsupported by historical evidence Parfitt 2002 Gonen 2002 Some commentators have suggested that these communities may have been established by Jewish traders usually men who brought their ideas and genes and converted members of the local population Goldstein 2008 Within these communities the contemporary composition may have been influenced by the number and origins of the founders as well as by the subsequent admixture events Forced and voluntary conversion out of the Jewish faith has been well documented and has left genetic imprint on some contemporary nonJewish populations Velez et al 2011Early population genetic studies based on blood groups and serum markers provided evidence that most Jewish Diaspora groups originated in the Middle East and that paired Jewish populations were more similar genetically than paired Jewish and nonJewish populations BonneTamir et al 1978a b 1977 Carmelli and CavalliSforza 1979 Karlin et al 1979 Kobyliansky et al 1982 Livshits et al 1991 These studies differed in their inferences regarding the degree of admixture with local populations Subsequent studies of the monoallelic Y chromosomal and mitochondrial DNA haplotypes demonstrated founder effects of both Middle Eastern and local origin but did not adequately resolve the degree of admixture To resolve this issue and to improve the understanding about the relatedness of contemporary Jewish groups our research teams and others have independently performed genomewide analyses of Diaspora Jewish groups and comparison with neighboring populations Atzmon et al 2010 Behar et al 2010 Campbell et al 2012 Kopelman et al 2009 Bray et al 2010 Listman et al 2010 These studies varied in the specific populations analyzed and in the number of individuals included from each population Yet they came to remarkably similar conclusions providing evidence for shared genetic ancestries among major Jewish Diaspora groups together with variation in admixture with local populations

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