The origin and history of the Ashkenazi Jewish population have long been of great
interest, and advances in high-throughput genetic analysis have recently provided
a new approach for investigating these topics. We and others have argued on the basis
of genome-wide data that the Ashkenazi Jewish population derives its ancestry from
a combination of sources tracing to both Europe and the Middle East. It has been claimed,
however, through a reanalysis of some of our data, that a large part of the ancestry
of the Ashkenazi population originates with the Khazars, a Turkic-speaking group that
lived to the north of the Caucasus region ~1,000 years ago. Because the Khazar population
has left no obvious modern descendants that could enable a clear test for a contribution
to Ashkenazi Jewish ancestry, the Khazar hypothesis has been difficult to examine
using genetics. Furthermore, because only limited genetic data have been available
from the Caucasus region, and because these data have been concentrated in populations
that are genetically close to populations from the Middle East, the attribution of
any signal of Ashkenazi-Caucasus genetic similarity to Khazar ancestry rather than
shared ancestral Middle Eastern ancestry has been problematic. Here, through integration
of genotypes from newly collected samples with data from several of our past studies,
we have assembled the largest data set available to date for assessment of Ashkenazi
Jewish genetic origins. This data set contains genome-wide single-nucleotide polymorphisms
in 1,774 samples from 106 Jewish and non-Jewish populations that span the possible
regions of potential Ashkenazi ancestry: Europe, the Middle East, and the region historically
associated with the Khazar Khaganate. The data set includes 261 samples from 15 populations
from the Caucasus region and the region directly to its north, samples that have not
previously been included alongside Ashkenazi Jewish samples in genomic studies. Employing
a variety of standard techniques for the analysis of population-genetic structure,
we found that Ashkenazi Jews share the greatest genetic ancestry with other Jewish
populations and, among non-Jewish populations, with groups from Europe and the Middle
East. No particular similarity of Ashkenazi Jews to populations from the Caucasus
is evident, particularly populations that most closely represent the Khazar region.
Thus, analysis of Ashkenazi Jews together with a large sample from the region of the
Khazar Khaganate corroborates the earlier results that Ashkenazi Jews derive their
ancestry primarily from populations of the Middle East and Europe, that they possess
considerable shared ancestry with other Jewish populations, and that there is no indication
of a significant genetic contribution either from within or from north of the Caucasus
region.
Copyright © 2014 Wayne State University Press, Detroit, Michigan 48201-1309.