Results are In: Jews Have A Lot In Common

The title is tongue in cheek. The research is real.

From Science Magazine:

Who are the Jews? For more than a century, historians and linguists have debated whether the Jewish people are a racial group, a cultural and religious entity, or something else. More recently, scientists have been weighing in on the question with genetic data. The latest such study, published today in the American Journal of Human Genetics, shows a genetic connection among all Jews, despite widespread migrations and intermarriage with non-Jews. It also apparently refutes repeated claims that most Ashkenazi Jews are descended from Central Europeans who converted to Judaism 1000 years ago.

The method and results:

Ostrer and his colleagues analyzed nuclear DNA from blood samples taken from a total of 237 Ashkenazi and Middle Eastern Jews in New York City and Sephardic Jews in Seattle, Washington; Greece; Italy; and Israel. They compared these with DNA from about 2800 presumably non-Jewish individuals from around the world. The team used several analytical approaches to calculate how genetically similar the Jewish groups were to each other and to the non-Jewish groups, including a method called identity by descent (IBD), which is often used to determine how closely two individuals are related.

Individuals within each Jewish group had high levels of IBD, roughly equivalent to that of fourth or fifth cousins. Although each of the three Jewish groups showed genetic admixture (interbreeding) with nearby non-Jews, they shared many genetic features, suggesting common roots that the team estimated went back more than 2000 years. Ashkenazi Jews, whose genetic profiles indicated between 30% to 60% admixture with Europeans, nevertheless clustered more closely with Middle Eastern and Sephardic Jews, a finding the researchers say is inconsistent with the Khazar hypothesis. "I would hope that these observations would put the idea that Jewishness is just a cultural construct to rest," Ostrer says.