The Missing Link of Jewish European Ancestry: Contrasting the Rhineland and the Khazarian Hypotheses

Abstract

The question of Jewish ancestry has been the subject of controversy for over two centuries and has yet to be resolved. The “Rhineland hypothesis” depicts Eastern European Jews as a “population isolate” that emerged from a small group of German Jews who migrated eastward and expanded rapidly. Alternatively, the “Khazarian hypothesis” suggests that Eastern European Jews descended from the Khazars, an amalgam of Turkic clans that settled the Caucasus in the early centuries CE and converted to Judaism in the 8th century. Mesopotamian and Greco–Roman Jews continuously reinforced the Judaized empire until the 13th century. Following the collapse of their empire, the Judeo–Khazars fled to Eastern Europe. The rise of European Jewry is therefore explained by the contribution of the Judeo–Khazars. Thus far, however, the Khazars’ contribution has been estimated only empirically, as the absence of genome-wide data from Caucasus populations precluded testing the Khazarian hypothesis. Recent sequencing of modern Caucasus populations prompted us to revisit the Khazarian hypothesis and compare it with the Rhineland hypothesis. We applied a wide range of population genetic analyses to compare these two hypotheses. Our findings support the Khazarian hypothesis and portray the European Jewish genome as a mosaic of Near Eastern-Caucasus, European, and Semitic ancestries, thereby consolidating previous contradictory reports of Jewish ancestry. We further describe a major difference among Caucasus populations explained by the early presence of Judeans in the Southern and Central Caucasus. Our results have important implications for the demographic forces that shaped the genetic diversity in the Caucasus and for medical studies.

No Evidence from Genome-Wide Data of a Khazar Origin for the Ashkenazi Jews

“…IBD analysis, which is focused on the most recent tens of generations of ancestry, is expected to generate tighter clustering of individuals within populations, between populations that have a recent common ancestral deme, or between populations that have recently experienced reciprocal gene flow (Gusev and others, 2009;Gusev and others, 2012). Our results contrast sharply with the work of Elhaik (Elhaik, 2013), which claimed strong support for a Khazar origin of Ashkenazi Jews. This disagreement merits close examination.…”

“…Elhaik (Elhaik, 2013) Jewish populations. The South Caucasus has been previously shown (Haber and others, 2013;Yunusbayev and others, 2012) (Baron, 1957;Ben-Sasson, 1976;De Lange, 1984;Mahler, 1971).…”

“…Specifically, our analysis highlighted the Armenian population, and to a lesser extent, the Azeri population, as the only Caucasus populations that present all genetic components also observed in Middle Eastern and North African populations. Thus, Armenians, used by Elhaik (Elhaik, 2013) as a potential proxy for a Khazar source population, could equally well have been employed as a misleading proxy for many populations across the Middle East with similar cluster memberships, thereby producing the same problematic interpretation that each such population is ancestral to Ashkenazi Jews.…”

“…One recent study (Elhaik, 2013), making use of part of our data set (Behar and others, 2010), focused specifically on the Khazar hypothesis, arguing that it has strong genetic support.…”

“…However, the reanalysis relied on the provocative assumption that the Armenians and Georgians of the South Caucasus region could serve as appropriate proxies for Khazar descendants (Elhaik, 2013). This assumption is problematic for a number of reasons.…”