Jewish communities in Europe and the Middle East share many genes inherited from the ancestral Jewish population that lived in the Middle East some 3,000 years ago, even though each community also carries genes from other sources  usually the country in which it lives.

That is the conclusion of two new genetic surveys, the first to use genome-wide scanning devices to compare many Jewish communities around the world.

A major surprise from both surveys is the genetic closeness of the two Jewish communities of Europe, the Ashkenazim and the Sephardim. The Ashkenazim thrived in Northern and Eastern Europe until their devastation by the Hitler regime, and now live mostly in the United States and Israel. The Sephardim were exiled from Spain in 1492 and from Portugal in 1497 and moved to the Ottoman Empire, North Africa and the Netherlands.

The two genome surveys extend earlier studies based just on the Y chromosome, the genetic element carried by all men. They refute the suggestion made last year by the historian Shlomo Sand in his book “The Invention of the Jewish People” that Jews have no common origin but are a miscellany of people in Europe and Central Asia who converted to Judaism at various times.