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. "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.
In addition, analyses of disease-related genes of higher prevalence in the Ashkenazi Jewish population indicate that only a minority of traits show signs of positive selection, suggesting that most have arisen through random genetic drift.
[...] 'We were surprised to find evidence that Ashkenazi Jews have higher heterozygosity than Europeans, contradicting the widely-held presumption that they have been a largely isolated group,' says first author Steven Bray, Ph D, a postdoctoral fellow in Warren's laboratory.
Family Tree DNA: Genetic Testing Service Get genetically tested to discover your relationship to other families, other Jews, and other ethnic groups. Abstract: "The Ashkenazi Jewish (AJ) population has long been viewed as a genetic isolate, yet it is still unclear how population bottlenecks, admixture, or positive selection contribute to its genetic structure.
Projects you might qualify to join include "Gesher Galicia - Jewish DNA Project", "Jewish Gen Belarus SIG DNA Project", "Jewish Gen Hungarian SIG DNA Project", "German Jewish Gersig DNA Project", "Jewish Frankfurt", "Sephardic Heritage DNA Project", "Jews of Rhodes Project", "The Jewish R1b Project", "Ashkenazi Levite R1a1", and "Jewish E Project". Here we analyzed a large AJ cohort and found higher linkage disequilibrium (LD) and identity-by-descent relative to Europeans, as expected for an isolate.
"Abraham's Children in the Genome Era: Major Jewish Diaspora Populations Comprise Distinct Genetic Clusters with Shared Middle Eastern Ancestry." The American Journal of Human Genetics 86:6 (June 3, 2010): pages 850-859.