Jews - Genetic Studies

Genetic Studies

Main article: Genetic studies on Jews See also: Y-chromosomal Aaron, Genealogical DNA test, and Matrilineality

Genetic studies indicate various lineages found in modern Jewish populations; however, most of these populations share a lineage in common, traceable to an ancient population that underwent geographic branching and subsequent independent evolutions. While DNA tests have demonstrated both inter-marriage and conversion to Judaism in all of the various Jewish ethnic divisions over the last 3,000 years, it was substantially less than in other populations. The findings lend support to traditional Jewish accounts accrediting their founding to exiled Israelite populations, and counters theories that many or most of the world's Jewish populations were founded entirely by local populations that adopted the Jewish religion, devoid of any actual Israelite genetic input.

DNA analysis further determined that modern Jews of the priesthood tribe—"Kohanim"—share an ancestor dating back about 3,000 years. This result is consistent for all Jewish populations around the world. The researchers estimated that the most recent common ancestor of modern Kohanim lived between 1000 BCE (roughly the time of the Biblical Exodus) and 586 BCE, when the Babylonians destroyed the First Temple. They found similar results analyzing DNA from Ashkenazi and Sephardi Jews. The scientists estimated the date of the original priest based on genetic mutations, which indicated that the priest lived roughly 106 generations ago, between 2,650 and 3,180 years ago depending whether one counts a generation as 25 or 30 years. These Jews belong to the haplotypes J1e and J2a. However, more recent research has shown that many ethnic groups in the Middle East and Mediterranean area also share this genetic profile.

Although individual and groups of converts to Judaism have historically been absorbed into contemporary Jewish populations, it is unlikely that they formed a large percentage of the ancestors of modern Jewish groups, and much less that they represented their genesis as Jewish communities.

Biologist Robert Pollack stated in 2003 that one cannot determine the biological "Jewishness" of an individual because "there are no DNA sequences common to all Jews and absent from all non-Jews". A 2009 study was able to genetically identify individuals with full or partial Ashkenazi Jewish ancestry.