August 07, 2012

Origins of North African and Central/East European Jews

A couple of new papers appeared yesterday. I'll just post the abstracts for the time being, and add any further comments as an update when I find the time for them.

Some related analyses of mine:

UPDATE (Aug 8):

Below is Fig. 3 from Campbell et al.:

One can see that Jewish groups have high degree of intra-population IBD sharing (A); many of the highest levels of IBD sharing is between Jewish groups (B and C).

This paper definitely shows that Jewish groups differ from non-Jewish North Africans. But, the lack of comparative samples from non-Jewish non-North Africans makes the interpretation of this result difficult. Both the PCA analysis, shown below, and the structure analysis indicates a significant Sub-Saharan component in North African non-Jewish populations.

So, it seems, based on these results, that Jewish groups are differentiated from North Africans due to their general lack of sub-Saharan admixture, and they also show a variable degree of affiliation to European groups; however, by "European" groups we go only as far as north Italy and Sardinia. What of the relationships of different Jewish groups to people from southern Italy, Greece, Anatolia, the Caucasus, or even Iranian speakers of the Near East?

Now, let's go to the Elhaik paper, which investigates a different problem altogether, trying to distinguish between the "Rhineland" and "Khazarian" hypotheses for the origins of Central-East European Jews. According to the paper:

Admixture calculations were carried out using a supervised learning approach in a structure-like analysis. This approach has many advantages over the unsupervised approach that not only traces ancestry to K abstract unmixed populations under the assumption that they evolved  independently (Chakravarti 2009; Weiss and Long 2009) but also problematic when applied to study Jewish ancestry, which can be dated as far back as 3,000 years (Figure 2). Admixture was calculated with a reference set of seven populations representing genetically distinct regions: Pygmies (Africa), French Basque (West Europe), Chuvash (East Europe), Han Chinese (Asia), Palestinians (Middle East), Turk-Iranians (Near East), and Armenians (Caucasus) (Figure 5).
But, Palestinians too have African admixture, so using them as a parental population conflates two separate issues: their old Near Eastern Semitic ancestors which could be reasonably inferred to be somewhat related to the Semitic ancestors of Jews, and their recent African admixture. Similarly, Turks have east Eurasian admixture, and Iranians have South Asian admixture.

The IBD sharing is probably the strongest piece of evidence in this paper for a Caucasian connection. Excess of IBD sharing with Caucasus and Palestinians relative to the other populations may indeed be a good indication of such admixture. On the other hand, the Khazarian Empire was primarily located in eastern Europe and the North Caucasus, not in Armenia and Georgia. Also, this analysis rejects the Greco-Roman hypothesis (whereby European Jews underwent admixture in Greco-Roman times when they were part of the Hellenistic and Roman Empires), but does not really include any Greco-Roman populations (for example, from Greece and Italy).

On the other hand, there may be something to the Khazar story (but in the sense of admixture, rather than replacement). High IBD sharing with Caucasians is one such piece of evidence. Another is the presence of Y-haplogroup Q and R-Z93+, both of which could in principle track a Central Asian Turkic influence (although Z93 could also track an Iranian influence). Then, there is the limited but persistent evidence for a little East Eurasian admixture present in Ashkenazi Jews and not in Sephardic Jews, which might also be consistent with a little Turkic influence.

Overall, I am convinced that most modern Jewish groups have some variable old Near Eastern Jewish ancestry, primarily on the basis of the elevated "Southwest Asian" that seems to correlate reasonably well with groups of Semitic speakers. But, it is difficult to say "how much" and to identify all the potential sources of admixture. Jews have been an international people for quite a long time, so I would guess that fragments of different peoples they encountered may remain in their genomes. Perhaps something akin to Ralph and Coop (2012) may give more information about the timing of these admixture events, as well as the date of the common ancestry of different Jewish groups.

PS: I started a small fastIBD analysis of different Jewish and non-Jewish groups with a fairly large assortment of populations, and will probably post it here in the next few days.

PNAS doi: 10.1073/pnas.1204840109

North African Jewish and non-Jewish populations form distinctive, orthogonal clusters

Christopher L. Campbell et al.

North African Jews constitute the second largest Jewish Diaspora group. However, their relatedness to each other; to European, Middle Eastern, and other Jewish Diaspora groups; and to their former North African non-Jewish neighbors has not been well defined. Here, genome-wide analysis of five North African Jewish groups (Moroccan, Algerian, Tunisian, Djerban, and Libyan) and comparison with other Jewish and non-Jewish groups demonstrated distinctive North African Jewish population clusters with proximity to other Jewish populations and variable degrees of Middle Eastern, European, and North African admixture. Two major subgroups were identified by principal component, neighbor joining tree, and identity-by-descent analysis—Moroccan/Algerian and Djerban/Libyan—that varied in their degree of European admixture. These populations showed a high degree of endogamy and were part of a larger Ashkenazi and Sephardic Jewish group. By principal component analysis, these North African groups were orthogonal to contemporary populations from North and South Morocco, Western Sahara, Tunisia, Libya, and Egypt. Thus, this study is compatible with the history of North African Jews—founding during Classical Antiquity with proselytism of local populations, followed by genetic isolation with the rise of Christianity and then Islam, and admixture following the emigration of Sephardic Jews during the Inquisition.


arXiv:1208.1092v1 [q-bio.PE]

The Missing Link of Jewish European Ancestry: Contrasting the Rhineland and the Khazarian Hypotheses

Eran Elhaik

The question of Jewish ancestry has been the subject of controversy for over two centuries and has yet to be resolved. The "Rhineland Hypothesis" proposes that Eastern European Jews emerged from a small group of German Jews who migrated eastward and expanded rapidly. Alternatively, the "Khazarian Hypothesis" suggests that Eastern European descended from Judean tribes who joined the Khazars, an amalgam of Turkic clans that settled the Caucasus in the early centuries CE and converted to Judaism in the 8th century. The Judaized Empire was continuously reinforced with Mesopotamian and Greco-Roman Jews until the 13th century. Following the collapse of their empire, the Judeo-Khazars fled to Eastern Europe. The rise of European Jewry is therefore explained by the contribution of the Judeo-Khazars. Thus far, however, their contribution has been estimated only empirically; the absence of genome-wide data from Caucasus populations precluded testing the Khazarian Hypothesis. Recent sequencing of modern Caucasus populations prompted us to revisit the Khazarian Hypothesis and compare it with the Rhineland Hypothesis. We applied a wide range of population genetic analyses - including principal component, biogeographical origin, admixture, identity by descent, allele sharing distance, and uniparental analyses - to compare these two hypotheses. Our findings support the Khazarian Hypothesis and portray the European Jewish genome as a mosaic of Caucasus, European, and Semitic ancestries, thereby consolidating previous contradictory reports of Jewish ancestry.



Unknown said...

If European Jews are substantially Caucasian as the paper claims, it is odd that they cluster so closely with Sephardic, Moroccan, and Syrian Jews, who presumably have little to no such admixture?

C.S. Sewell said...

im thankful for the information emerging on jewish ancestors origins my self, as someone of partial jewish descent. thank you D. for all ypour postings and helping us lay folks stay informed!

Onur said...

There is the question how much modern populations represent ancient populations. This holds true for virtually every part of the world, even for the regions that have preserved their languages all along. In the absence of ancient DNA, the best thing to do is to apply as many methods of genetic analysis as possible on as many relevant modern populations as possible to test various hypotheses. Eran Elhaik apparently tried to do just that. How successful he is is open to debate.

Ashtaga said...
This comment has been removed by the author.
Dienekes said...

Well, analysis of Mozabites indicates that the African ancestry is 100-131 generations old:

I'd say that different factors contribute to the fact that they're different; Sub-Saharan in Muslims and West_Asian in Jews, for example.

Ashtaga said...

Update : At times you do not make sense. North African Jews differ from North Africans because they are relatively very recent West Asian newcomers (late Classical Antiquity and 1492 Inquisition). It has nothing to do with the African ancestry of North Africans which is actually native to North Africa. If you compare North African Jews to their Muslim counterparts , you can see the Jews have very high Caucasus/West Asian ancestry , totally nearly absent in the formers. Note that the common SW Asian and especially prominent Mediterranean ancestry in Jews , North Africans , Levantines and South Europeans (Sardinians , Cypriots etc..) reflect a common Human settling of the Mediterranean shores however

Ashtaga said...

I do acknownledge that Mozabites have some recent West African ancestry. That is mostly why they drag towards SSA , more so than North_Moroccan , Tunsian and Algerian samples.

ryan said...

There's something odd about the elHaik paper. I can't find anything that bears out his reference to Druze as a primarily Turkic people. Historically, the movement seems to come from Egypt and quickly land in the Jebel Druze. The wiki page has a pretty wide-ranging discussion of recent data and pre-genetic testing theories of Druze origins, and none of them mention Turkic stock. One mentions Turkish Cypriot clustering, but that's a shaky bridge toward a Turkic origin.

Dienekes said...

I think it's careless use of language, because the Druze are analyzed in supervised admixture analysis with Turks as a parental population. The Druze are indeed more "Anatolian-like" than "Palestinian-like".

Eran Elhaik said...

Thank you for reviewing my paper. First, regarding the admixture analysis and the choice of Palestinians as ancestral group to Jews. That choice is justified by the common Semitic origin of the Hebrews and the Palestinians and their continuous admixture throughout history. Palestinians have some Northern African ancestry, but that does not disqualify them as proper surrogate population as it may derive from admixture with the Egyptian, which is again, part of Judean history. The important point about the admixture analysis is that Eastern European Jews share a very large portion of Caucasus ancestry that is otherwise restricted to Caucasus populations.

As for the Druze, they were analyzed with a combined group of Iranian and Turks. Ryan correctly stated that the movement began in Egypt but the large stock of people came from Iran and the southern Turkic region. They migrated to Lebanon and Israel in the 13th century. Shlush et al. (2008) and myself traced their origin to the near east, which explains the proximity to Eastern European Jews (common Turkic origin), yet no overlap.

Roy King said...

I was wondering which Caucasus populations comprised the IBD comparisons with East European Jews. Hopefully not the Azeri/Mountain Jews, but in any case, it would be worthwhile for the authors to present the IBD's with specific Caucasus populations.

Onur said...

BTW, I disagree with a great majority of Eran Elhaik's conclusions (=his interpretation of the results). I only commend him for his use of many methods of genetic analysis on a dense population dataset.

Sgt. Gil said...

Are we missing something over the semantics of “Semitic origin,” as a large portion of Jewish ancestry [J2a, G, R etc] were unlikely to originally have been Semitic-language speakers and were possibly part of the Hurrian migrations [Gibeon, Kephirah, Beeroth and Kiriath-Jearim were “Hivite” cities that became Judah-ite - Joshua 9]. The Jewish people were a “mix” from the beginning with some strong Anatolian [and Caucasus-?] roots.

terryt said...

"The Jewish people were a 'mix' from the beginning"

Exactly. As is every human population. There is no such thing as a purebred human population.

Anthony said...

Interstingly, as much as this paper actually proves anything, it also disproves the anti-semitic variant of the Khazar Hypothesis, which states that there is *no* genetic link between the Jews of ancient Judea and the Jews of Eastern Europe.

Sgt. Gil said...

Yes, all people are a mix, but in the context of Eran Elhaik's paper to what degree are Anatolian/Caucasian elements among Jews from 600 AD or 3,000 BC?

An extinct Judaeo-Slavic language [K'naan] was said to have been used in Eastern Europe centuries ago; it was replaced by Yiddish. This would indicate [to me] that a large and dominating migration came eastward into Slavic lands. A Khazar-influence on Jewry [in my opinion] is probable. What is unknown is the extent.

Creative said...

@Sgt. Gil
As someone who tries to stay neutral and as someone who is of Palestinian Christian descent and Haplo G carrier, let me say this: I have no doubt that the majority of people in the ME carry a ancient Semitic component in them via admixture. For instance a married in relative of mine is by his own account a descendent of nomadic Arab Christian-Bedouins.
Plus, I never believed that all of today’s Arab-Bedouins are all actually pure ethnic Arabs, but rather likely represent older Semitic layers, this can be observed with the Nabateans who represent Arab and semi-nomadic Aramaic layers. Plus you have the linguistic process of Aramaic/Arab - ization.
(It would be interesting to see a breakdown on all Arabic speaking Bedouins.)

Also I have the impression there is a process of seeing Canaanites under every rock in the Levant as a result of today’s geopolitical tensions. Ignoring the semitization of other ancient non-Semitic populations in the region. I wouldn’t be surprised if there was a difference in the ancient population structure along the coasts of the Levant and the populations living more inland. Gaza for instance was heathen to the core till they were forced to convert to Christianity in 407 A.D.

edrnch said...

I wonder what is known from genetic studies of *Western* Ashkenazim specifically. They seem to be grouped together, apparently, with Eastern Ashkenazim in the recent studies, if they are even included. Linguistic research shows that the language of Western Ashkenazim spoken as a dialect among themselves is directly related to Eastern European Yiddish; however, with no Slavic component. The two languages clearly had a common root, and then diverged when the major portion of the German Jewish population migrated to eastern Europe and later merged with other Jewish groups. Genetic studies of Western Ashkenazim would help to reveal the origins of Jews before their journey into Eastern Europe. I have read that there is some sort of discernible genetic difference between eastern and western Ashkenazim, but have not been able to find information beyond that. I would guess the two populations are still very close, but that studies of Western Ashkenazim would be revealing. Have these studies been done? In a generation there will be many fewer W. Ashkenazim to study. The community is relatively small and "intermarrying" with other Jewish groups. Does anyone know?