Genetic studies of Jews

Genetic studies of Jews are part of the population genetics discipline and are used to analyze the chronology of Jewish migration accompanied by research in other fields, such as history, linguistics, archaeology, and paleontology. These studies investigate the origins of various Jewish ethnic divisions. In particular, they examine whether there is a common genetic heritage among them. The medical genetics of Jews are studied for population-specific diseases.

Studies on Jewish populations have been principally conducted using three types of genealogical DNA tests: autosomal (atDNA), mitochondrial (mtDNA), and Y-chromosome (Y-DNA). atDNA tests, which look at the entire DNA mixture, show that Jewish populations have tended to form genetic isolates – relatively closely related groups in independent communities with most in a community sharing significant ancestry – with Ashkenazi Jews forming the largest such group. mtDNA and Y-DNA tests look at maternal and paternal ancestry respectively, via two small groups of genes transmitted only via female or male ancestors.

Genetic analysis reveals a major genetic descent of Jewish groups from the Levant or Near East, accompanied by admixture and introgression with non-Jewish host populations, varying among different Jewish communities. Studies on the genetic composition of Ashkenazi, Sephardi and Mizrahi Jewish populations of the Jewish diaspora shows significant amounts of shared Middle Eastern ancestry. Several Jewish groups show genetic proximity to Lebanese, Palestinians, Bedouins, and Druze in addition to Southern European populations, including Cypriots and Italians. Jews living in the North African, Italian, and Iberian regions show variable frequencies of admixture with the historical non-Jewish population along the maternal lines. In the case of Ashkenazi and Sephardi Jews (in particular Moroccan Jews), who are closely related, the source of non-Jewish admixture is mainly southern European. Some researchers have remarked on an especially close relationship between Ashkenazi Jews and modern Italians. Some studies show that the Bene Israel and Cochin Jews of India, and the Beta Israel of Ethiopia, while very closely resembling the local populations of their native countries, may have some ancient Jewish descent.