Friday, June 04, 2010

Jewish genetics

NEW RESEARCH shows a shared genetic pattern for Jews from widely dispersed communities:
Study finds genetic links among Jewish people

Published: Thursday, June 3, 2010 - 12:55 in Health & Medicine (Eureka Science News)

Using sophisticated genetic analysis, scientists at Albert Einstein College of Medicine of Yeshiva University and New York University School of Medicine have published a study indicating that Jews are a widely dispersed people with a common ancestry. Jews from different regions of the world were found to share many genetic traits that are distinct from other groups and that date back to ancient times. The study also provides the first detailed genetic maps of the major Jewish subpopulations, a resource that can be used to study the genetic origins of disease. The findings appear in the June 3 online issue of the American Journal of Human Genetics.

[...]

The researchers found that Jews from the major Diaspora groups formed a distinct population cluster, albeit one that is closely related to European and Middle Eastern non-Jewish populations. Each of the Diaspora groups also formed its own cluster within the larger Jewish cluster. Further, each group demonstrated Middle-Eastern ancestry and varying degrees of mixing with surrounding populations. The genetic analysis showed that the two major groups, Middle Eastern Jews and European Jews, diverged from each other approximately 2,500 years ago.

"The study supports the idea of a Jewish people linked by a shared genetic history," said Dr. Ostrer of NYU. "Yet the admixture with European people explains why so many European and Syrian Jews have blue eyes and blond hair."

[...]
This is about what I would expect.

An article in Science Now covers the same study and notes that it does not support Sholmo Sand's arguments in The Invention of the Jewish People and it neither supports nor completely rules out the claim that Ashkenazi Jews descend from the Turkic Khazars. It adds this:
The study does not address the status of groups whose claim to Jewishness has been controversial, such as Ethiopian Jews, the Lemba from southern Africa, and several groups from India and China. But given the findings of a common genetic origin plus a complex history of admixture, geneticist David Goldstein of Duke University in Durham, North Carolina, says that neither of the "extreme models"—those that see Jewishness as entirely cultural or entirely genetic—"are correct." Rather, Goldstein says, "Jewish genetic history is a complicated mixture of both genetic continuity from an ancestral population and extensive admixture."
For the Lemba, go here and follow the many links. Also, a recent AP article surveys Tudor Parfitt's theories about them and brings in some criticisms from other historians.

UPDATE: The LA Times has the genetics story here. And Joseph Lauer notes a link to the American Journal of Human Genetics article here. The abstract reads:
For more than a century, Jews and non-Jews alike have tried to define the relatedness of contemporary Jewish people. Previous genetic studies of blood group and serum markers suggested that Jewish groups had Middle Eastern origin with greater genetic similarity between paired Jewish populations. However, these and successor studies of monoallelic Y chromosomal and mitochondrial genetic markers did not resolve the issues of within and between-group Jewish genetic identity. Here, genome-wide analysis of seven Jewish groups (Iranian, Iraqi, Syrian, Italian, Turkish, Greek, and Ashkenazi) and comparison with non-Jewish groups demonstrated distinctive Jewish population clusters, each with shared Middle Eastern ancestry, proximity to contemporary Middle Eastern populations, and variable degrees of European and North African admixture. Two major groups were identified by principal component, phylogenetic, and identity by descent (IBD) analysis: Middle Eastern Jews and European/Syrian Jews. 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.