The researchers were able to estimate that between 35 and 55 percent of the modern Ashkenazi genome comes from European descent.

[...] He adds that his group's analysis agrees with a recently published study from New York University and Albert Einstein College of Medicine, and supports estimates of a high level of European admixture, accounting for up to half of the genetic make-up of contemporary Ashkenazi.

Excerpts: "Different communities of Jews around the world share more than just religious or cultural practices -- they also have strong genetic commonalities, according to the largest genetic analysis of Jewish people to date.

But the study also found strong genetic ties to non-Jewish groups, with the closest genetic neighbours on the European side being Italians, and on the Middle Eastern side the Druze, Bedouin and Palestinians.

Researchers in New York and Tel Aviv conducted a genome-wide analysis on 237 individuals from seven well-established Jewish communities around the world, hailing from Iran, Iraq, Italy, Greece, Turkey, Syria and eastern Europe.

The team then compared these genetic profiles to those of non-Jews in the same geographic regions based on data from the Human Genome Diversity Project....

"Signatures of founder effects, admixture, and selection in the Ashkenazi Jewish population." Proceedings of the National Academy of Sciences of the United States of America (PNAS) 1 (September 14, 2010): pages 16222-16227. Among the comparative populations were 1705 continental Europeans and 1251 European-Americans.

Recent reports have reaffirmed that the AJ population has a common Middle Eastern origin with other Jewish Diaspora populations, but also suggest that the AJ population, compared with other Jews, has had the most European admixture.

The IBD segment sharing and the proximity of European Jews to each other and to southern European populations suggested similar origins for European Jewry and refuted large-scale genetic contributions of Central and Eastern European and Slavic populations to the formation of Ashkenazi Jewry.

Rapid decay of IBD in Ashkenazi Jewish genomes was consistent with a severe bottleneck followed by large expansion, such as occurred with the so-called demographic miracle of population expansion from 50,000 people at the beginning of the 15th century to 5,000,000 people at the beginning of the 19th century.

Thus, this study demonstrates that European/Syrian and Middle Eastern Jews represent a series of geographical isolates or clusters woven together by shared IBD genetic threads." "The genetic, cultural and religious traditions of contemporary Jewish people originated in the Middle East over three thousand years ago.