DNA Studies of Jews are Shallow

 

While genetic studies do provide valuable information about human populations, they do not tell the whole story. In part, this is because most are very shallow. That is to say, they usually do not trace genetic inheritance beyond 2000 years ago. 

Around 40% of the Ashkenazi of Europe have mtDNA from 4 founding mothers who lived about 1000 years ago. Those women are believed to have had Middle Eastern ancestry. Given that the Hebrew ruler-priests were widely dispersed 4000 years ago, this study is very shallow. It also suggests that the Ashkenazi did not consistently practice endogamous marriage.

On the other hand, the Sephardi (Spanish/Portuguese) and Mizrahi (Middle Eastern/North African) trace maternal ancestry overwhelmingly back to a West Eurasian and Middle Eastern pool, with some overlap with long existent populations of the Fertile Crescent, such as the Druze.

James Henry Breasted's map of the Fertile Crescent.

 
Modern Jews can attribute about 3 to 5 percent of their ancestry to sub-Saharan Africans. However, in the Mizrahi communities, sub-Saharan mtDNA is negligible, suggesting that the Mizrahi populations remained endogamous. 

The primary Jewish populations that trace DNA to the Nile Valley are North African and Ethiopian Jews.

Genetic, historical, and genealogical studies reveal evidence of endogamy among Sephardi Jews. Despite centuries of geographical dispersal following the 1492 expulsion from Iberia, Sephardic communities retained distinct ancestral markers and tightly knit community structures.

Why are the DNA studies of Jews so shallow?

DNA studies of Jewish populations are "shallow" because the research has focused primarily on the last 500 to 2,000 years. This timeframe addresses the era of the Jewish diaspora, and the DNA of Ashkenazi Jews. Tracing genetic ancestry of Jews deeper into ancient times would raise doubts about the prevalent Jewish narrative that bolsters the Zionism of many who left Europe for Isarel. Jewish researchers admit that their genetic studies are limited by the destruction of historical records, limited DNA samples, and their own Jewish history. A significant number of pioneering geneticists who study Jewish populations are Jews affiliated with Israeli and US research hospitals.

On the Y-DNA side, researchers have concentrated on the Cohanim marker said to be evidence of descent from the "tribe" of Levi. While Cohanim from diverse backgrounds carry a total of 21 Y chromosome haplogroups, 5 haplogroups account for 79.5% of Cohanim Y chromosomes. They are haplogroup J-P58 (formerly referred to as J1e), the most recent and frequent lineage, accounting for 46.1% of Cohanim chromosomes. It is strongly prevalent in the Near East and contains the extended Cohen Modal Haplotype (CMH).

Haplogroup J-M410 (formerly J2a) accounts for 14.4% of Cohanim Y chromosomes and contains an extended modal haplotype also unique to Cohanim. 

Haplogroup E-M78 (or E1b1b)

Haplogroup G-P15 (or G-M285 / G-M377)

Haplogroup R-M269 (or R1b). This map shows its distribution in red. 

Haplogroup R1b

The major dispersal of Haplogroup R1b populations occurred in two waves between 10,500 and 4,000 years ago. However, ancient R1b lineages date to the Late Paleolithic. In the Iron Age, sub-lineages expanded widely due to cattle domestication and Bronze Age metallurgical advancements. 

Digging Deeper

The genetic sequences of Haplogroup X diverged from Haplogroup N which originated in the region of the Lower Nile. Haplogroup X diverged about 30,000 years ago with two sub-groups X1 and X2 now identified. Overall Haplogroup X accounts for about 2% of the population of Europe, the Near East, and North Africa.

The heaviest concentration of mtDNA haplogroup X is in Eastern Canada. The next highest concentration, about 40%, is found in the Druze of the Middle East.

Sub-group X1 is strongly present in the Near East, the Caucasus, and Mediterranean Europe. Sub-group X2 appears to have undergone population expansion and dispersal after the last glacial maximum, between 21,000 and 18,000 years ago. There are concentrations of sub-group X2 in Georgia (8%), the Orkney Islands (7%) and among the Israeli Druze (27%), most of whom live in Galilee.

Still Deeper

The genetic root of modern humans is mtDNA Haplogroup L which has its roots in Africa. 

Related reading: The population genetics of the Jewish people - PMC; Sub-Saharan DNA of Modern Jews; A Kindling of Ancient Memory; The Hebrew Selection of Marriage Partners; DNA Suggests Early Jewish Links with Africa - Biblical Archaeology Society; Extended Y chromosome haplotypes resolve multiple and unique lineages of the Jewish priesthood - PMC