Multiple Origins of Ashkenazi Levites: Y Chromosome Evidence for Both Near Eastern and European Ancestries

Behar et al. - 2003

Abstract

Previous Y chromosome studies have shown that the Cohanim, a paternally inherited Jewish priestly caste, predominantly share a recent common ancestry irrespective of the geographically defined post-Diaspora community to which they belong, a finding consistent with common Jewish origins in the Near East. In contrast, the Levites, another paternally inherited Jewish caste, display evidence for multiple recent origins, with Ashkenazi Levites having a high frequency of a distinctive, non–Near Eastern haplogroup. Here, we show that the Ashkenazi Levite microsatellite haplotypes within this haplogroup are extremely tightly clustered, with an inferred common ancestor within the past 2,000 years. Comparisons with other Jewish and non-Jewish groups suggest that a founding event, probably involving one or very few European men occurring at a time close to the initial formation and settlement of the Ashkenazi community, is the most likely explanation for the presence of this distinctive haplogroup found today in > 50% of Ashkenazi Levites

Introduction

Jewish identity, since at least Talmudic times (100B.C.E.–500 C.E.), has been acquired either by maternal descent from a Jewish woman or by rabbinically authorized conversion. Only in recent years have some strands of the Jewish religion accepted paternal descent as a qualifying criterion. Within the Jewish community.  However, membership in the three male castes (Cohen, Levi, and Israelite) is determined by paternal descent.  Cohanim (plural of “Cohen,” the Hebrew word for priest) are, in Biblical tradition, the descendants of Aaron the brother of Moses; Levites are, in that tradition, considered to be those male descendants of Levi, the third son of the patriarch Jacob and paternal ancestor of Aaron, who are not Cohanim. The Cohanim have both rights and duties in religious law, as well as being subject to restrictions that do not apply to the other castes. They are, for example, called first to the reading of the Torah in synagogue and forbidden entry into a cemetery.  Levites have some rights similar to those of Cohanim (for example, exemption from payment of a special tax on the birth of a first-born male) but are not subject to the particular restrictions placed on the Cohanim. Strict adherence to the qualifying rules would mean that the male descendants of men who were not Jews at birth could be Israelites but not Cohanim or Levites (Encyclopaedia Judaica 1972). It is estimated that Cohanim and Levites each comprise 4% of the Jewish people (Bradman et al. 1999). In addition to classification by caste, Jews, on the basis of their ancestry and religious practice, can be assigned to one or other of a few long-standing, geographically separated Jewish communities, the most numerous of which are the Ashkenazi and Sephardi groupings (Reif 1993). The term “Ashkenaz” describes a relatively compact area of Jewish settlement in northwestern Europe, including northeastern France and northern Germany, where Jewish settlement is documented dating back to at least the 6th century C.E. From the 10th century, Ashkenazi Jews spoke a common language (Yiddish), written with Hebrew characters but borrowing its lexicon mostly from German. By the 16th century, Jews speaking this language and following the Ashkenazi religious rite and cultural tradition populated communities extending from the Loire in the west to the Dnieper in the east and from Rome in the south to the Danish border in the north. During the past 500 years, there has been rapid population growth, culminating in an estimated population size of 8 million Ashkenazi Jews just prior to the outbreak of WorldWar II.   There is uncertainty concerning the relative contributions to Ashkenazi Jewry of, on one hand, western versus eastern immigration of Jews and, on the other hand, internally generated population growth versus conversion to Judaism. In particular, it has been suggested that subjects of the Khazar Empire (located to the northeast of the Black Sea), who had adopted Judaism in the last quarter of the first millennium C.E., were an important constituent of the nascent Ashkenazi community (Encyclopaedia Judaica 1972).  The term “Sephardi” originally described Jews descended from the communities that existed in Spain prior to the expulsion in 1492 C.E. However, current usage applies this designation to all descendants of the communities of North Africa and the Near East who follow the Sephardi rite of worship and cultural traditions. It is thought that, prior to the middle of the 20th century, gene flow between the Ashkenazi and non- Ashkenazi groups was relatively restricted.