Jewish population history and genetics

Historical facts

The main historical Jewish diaspora events are well known:

Estimates and assumptions

  • Jerusalem at its fall 70 CE contained ca. 600,000 persons; together with nearby settlers and defenders possibly ca. 1 million. Of those surviving, ca. 100,000 were sold as slaves. Egypt in the first century CE probably had 1/8 Jews (ca. 1 million). The same population size is estimated for Syria and for Jews in other places.
  • Slave populations may have served as the basis of later European Jewish communities.
  • 1170 CE Benjamin of Tudela gives estimates with 10% of the Jews attributed to Persia and India, 10% to Arabia, probably 500,000 in total in the countries he visited, and 750,000 altogether.
  • Modern Jewish ancestry probably owes about as much to converts from the first millennium to the beginning of the Middle Ages as it does to the Jews of antiquity (Howard Adelman, Elazar Barkan, Gil Atzmon).
  • To a larger degree, modern Ashkenazi Jews are the descendants of Jews who migrated into northern France and Rhineland-Germany (“Yiddish-culture”) around 800–1000 CE, later migrating into Eastern Europe. Many Ashkenazi Jews also have mixed Sephardic origins, as a result of exiles from Spain, first during Islamic persecutions (11th-12th c.) and later during Christian reconquests (13th-15th c.) and the Spanish Inquisition (15th-16th c.).
  • A series of bottlenecks is assumed/confirmed: a) Exile from Israel b) Emigration from Italy c) Persecution in Europe d) Holocaust likely terminating many of the Y-, mt, and autosomal DNA diversity.

Genetic facts

  • 2010 studies (Atzmon et al, Behar et al) show autosomally modern Ashkenazi and Sephardi share a common ancestry and have roughly 30% European ancestry with the rest being Middle Eastern with a dominant Levantic component.
  • 2014 a genomes study (Carmi et al.) compared 128 Ashkenazim to 26 Flemish finding a genetic bottleneck. Cochran improved the study estimates to 300-500 ancestors 30-38 generations (ca. 900-1150 years) ago and doubted the comparison is sufficient to estimate 46-50% European ancestry in modern Ashkenazim.