Originally Posted by Mike33

1991, Livshits et al compared twelve pairs of Jewish and non-Jewish populations from the Middle East, North Africa, and Europe with each Jewish/non-Jewish pair sharing the same (or close) geographic area: Yemen, Iran, Iraq; Morocco and Libya; Poland, Russia, and Georgia; Germany and Czechoslovakia; Bulgaria and Turkey/Spain (Turkish Jews were compared to Spanish non-Jews because most Turkish Jews were exiled from Spain by the Inquisition). Their conclusion: modern Jewish populations in general derived from an earlier common gene pool which had undergone relatively little admixture with non-Jewish neighbors after dispersal from Israel. Somewhat differently, Kurdish Jews had experienced considerable interaction with non-Jewish Kurds, and Yemenite Jews may have had a substantial component of different genes from conversion into Judaism (p. 145).

In 1993, Santachiara et al compared eighty-three Sephardim (mostly from Tunisia and Morocco), eighty-three Ashkenazim (mostly from Russia and Poland), and 105 non-Jews from Czechoslovakia, and made comparisons to non-Jews from Lebanon. They found strong genetic affinities between Sephardim and Ashkenazim, almost no relationship with non-Jews from Czechoslovakia, and a very close relationship between Sephardim and Lebanese non-Jews. They found about 23.4% to 28.6% non-Jewish Y-chromosomes in the Ashkenazim, and concluded that this represented about one percent or less of admixture per generation for the centuries the Ashkenazim had lived in Central or Northeastern Europe

In 2004, Behar et al compared data from Ashkenazi groups in ten different European areas (France, Germany, the Netherlands; Austria-Hungary, Byelorussia, Lithuania, Poland, Romania, Russia, and Ukraine ) with data from non-Jewish groups in seven different countries (France, Germany, Austria, Hungary, Poland, Romania, and Russia). They found that nine of the Jewish groups were similar, with low rates of admixture with non-Jewish groups, but that these Ashkenazi groups were closely related to non-Ashkenazi Jews and to some non-Jewish Near Eastern groups. Within Europe, these authors suggested an admixture rate of 5-8% for all the Jewish nationality groups except Dutch Jews who had an admixture rate of 46.0% plus or minus 18.3%. This supposedly resulted from a long history of relative tolerance from non-Jews, with Jewish women marrying non-Jewish men (p. 362).