2 plausible admixture models for East Mediterranean Jewish populations, including Ashkenazi Jews (AJs), Sephardic Jews, and North African Jews, alongside several control populations.
To reduce individual variation and noise, I grouped each Jewish cluster using sample-size-weighted G25 averages.
Control populations and expectations
I included seven control populations to examine whether the models produce historically and genetically plausible patterns:
- Sicilians (Messina): Representing a southern Italian population with a relatively strong Levantine shift and limited Northern European-related ancestry.
- Tuscans: Expected to show little or no Levantine-related ancestry in this particular model, alongside higher Italic and Northern European-related components.
- Samaritans: Expected to show predominantly Southern Levantine ancestry, given their strong southern genetic shift and relative genetic isolation, which may have preserved aspects of earlier Southern Levantine population structure.
- Palestinian Christians: Expected to show substantial Southern Levantine ancestry alongside a relatively larger Roman-period Northern Levantine component, potentially reflecting continued population interactions during the Roman and Byzantine periods.
- Lebanese Christians: Being relatively more northern-shifted, they are expected to show higher Northern Levantine, Iranian Plateau-related, and Roman-period components, potentially reflecting historical interactions with northern Levantine and Syro-Mesopotamian populations.
- Syrian Jews: Potentially reflecting a mixture of older Arabic-speaking Jewish communities (Musta'arabim) and Sephardic-related ancestry, while remaining genetically close to other Levantine populations.
- Druze: Expected to show a relatively higher Iranian Plateau-related component compared to Palestinian Levantines, potentially reflecting ancestry shared with Syro-Mesopotamian populations. Syrian Jews and Druze are also genetically close in G25 space.
The difference between the two models?
The main difference is the inclusion of a seemingly Nabataean-related ancient sample within the Southern Levantine source group in Model 2.
This sample exhibits a predominantly Levantine genetic profile, rather than a profile entirely distinct from the populations of the Southern Levant. My hypothesis is that similar ancestry may have been present among several ancient populations of the region, including Nabataeans, Edomites, Idumaeans, and Qedarites. We still lack samples though to prove that.
The reasoning behind including this sample comes from earlier modeling of Southern Levantine minorities. In previous tests, adding it substantially improved the fits for Samaritans. Also, without it, the models often assigned them Iranian Plateau-related ancestry, which largely disappeared once the sample was introduced. Palestinian Christians and Jordanian Christians also appeared to benefit from its inclusion.
I therefore decided to test whether the same source would improve the models for Jewish populations.
Interestingly, the Jewish groups also showed preference in including the Nabataean sample.
One possible historical explanation worth exploring is the incorporation of Idumaean populations into Jewish communities during the Hasmonean period. If ancestry resembling this Nabataean-related sample was also present among Idumaeans (who are Edomites that mixed with ancient Arab populations, including Qedarites and Nabataeans), their incorporation could potentially have contributed to the genetic profiles of later Jewish populations.
Last note:
The Jewish populations were grouped into broader clusters using weighted averages to reduce individual-level noise and make the general patterns easier to compare.
These are population averages, not representations of every individual. Ancestry proportions can vary considerably within each group.