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Thursday, January 17, 2013

Sloppy "Khazar" genetic research gets publicity from AFP

From AFP, in a story presumptuously titled "Gene study settles debate over origin of European Jews":
Jews of European origin are a mix of ancestries, with many hailing from tribes in the Caucasus who converted to Judaism and created an empire that lasted half a millennium, according to a gene study.

The investigation, its author says, should settle a debate that has been roiling for more than two centuries.

Jews of European descent, often called Ashkenazis, account for some 90 percent of the more than 13 million Jews in the world today.
That last paragraph comes straight from the paper, and shows already how sloppy the paper is. Of course, far fewer than 90% of Jews today are Ashkenaz; the paper misquoted that statistic from an article about American Jews. Seth Frantzman in JPost showed this and other sloppiness about this study a few weeks ago.

AFP, of course, cannot be trusted to actually do any fact checking.

Seeking new light in the argument, a study published in the British journal Genome Biology and Evolution, compares the genomes of 1,287 unrelated individuals who hail from eight Jewish and 74 non-Jewish populations.

Geneticist Eran Elhaik of the Johns Hopkins School of Public Health in Baltimore, Maryland, trawled through this small mountain of data in search of single changes in the DNA code that are linked to a group's geographical origins.
Frantzman shows that Elhaik makes assumptions about history that are simply not true:
However, the real flaws in this new research are historical. The author claims a massive knowledge of history that has major implications for his findings.

“There are no records of Caucasus populations mass-migrating to Eastern and Central Europe prior to the fall of Khazaria.”

The footnote for this is another genetic research study, but a claim like this requires historical knowledge of the Caucuses. In fact, the Caucuses were a place of great human movement from the 15th to 19th centuries. Cossacks, Circassians, Chechans, Tatars and numerous other groups roamed the region in the period, some of whom, like the Khazars, vanished to history.

The author claims that his evidence shows that “Judaized Greco-Roman male-driven migration directly to Khazaria is consistent with historical demographic migrations and could have created the observed pattern.” Following in the footsteps of Tel Aviv University academic Shlomo Sand’s work, The Invention of the Jewish People, Elhaik claims “no Jewish historiography was produced from the time of Josephus Flavius (1st century CE) to the 19th century.”

But the source, Sand, is not an expert on Jewish history in the period – his book, like Koester’s, was more a polemic.

Elhaik goes further, noting that “the religious conversion of the Khazars encompassed all the Empire’s citizens and subordinate tribes and lasted for the next 400 years…the Judeo- Khazars fled to Eastern Europe and later migrated to Central Europe and admixing with the neighboring populations.”

There is actually no evidence of this; the general view has been that only some of the Khazar elite converted to Judaism.

Yet Elhaik even claims to know the details of the Judeo-Khazar life. “After the decline of their Empire, the Judeo-Khazars refugees sought shelter in the emerging Polish Kingdom and other Eastern European communities, where their expertise in economics, finances, and politics were valued.”

The source for much of this is Koestler, passed off as fact with no mention that Koestler simply inferred most of it from his imagination and theories. 
In other words, Elhaik uses as source material Shlomo Sand and Arthur Koestler, who are more akin to fiction writers than serious researchers!

There is evidence that Elhaik was predisposed to find Khazar connections when evidence does not support it. He started a crowdsourcing project to raise money for his paper, and called it "The Khazar DNA project."

It sounds like he reached his conclusion before he did his research.

But what do experts on European genetics think? The author of the European Genetics and Anthropology Blog is more than a little skeptical of Elhaik's claims:

I think the author fumbled the interpretation of the results.

His mistake was treating the Armenian reference sample as a Caucasus group, and also a proxy for the gene pool of the Khazar Empire. Thus, when the Jewish samples showed strong affinity to the Armenians, the author mistook this as a signal of Khazar ancestry in Jews, because the Khazar Empire included parts of the Caucasus.

But what do modern Armenians of the South Caucasus have to do with ancient Khazars of the Pontic Caspian Steppe? Not much, I'd say. Armenians aren't even a useful Caucasian reference set, in my opinion. They're better treated as an Eastern Anatolian group, due to their high affinity to Mediterranean and Middle Eastern populations.

Moreover, they show low North/East European input, and very little East Eurasian influence, which is actually the sort of stuff we'd want in a proxy for the inhabitants of the Khazar Empire in what is now Southern Russia.

All those looking for Khazar influence in Jews should be aware that the Eurasian steppes are part of the Northern world, and this has been the case for thousands of years. We know this from ancient DNA, from samples all the way from what is now Ukraine to South Siberia. This Northern world is separated from the Southern world by some mighty barriers to gene flow, like the Black Sea, Caucasus Mountains and the deserts of Central Asia (see here).

Based on my own analyses of Jewish genomes, I'd say that Ashkenazim Jews are genetically an Eastern Mediterranean group, but with various other admixtures, like Western European, Eastern European, Eastern Anatolian, and even African and East Asian. Does that mean ancestry from the Khazar Empire? Perhaps in part, but it's hard to say for sure.

So, what could be a sure signal of Khazar influence in modern Jews? The best bet is probably the R1a-Z94 carried by many Ashkenazim Levites. This marker is very common in modern Indo-Iranian and Turkic groups, so it's not difficult to imagine its presence in ancient Khazaria. The only problem is that it's also seen in Semitic groups, like Arabs. That's why it's not possible to say at the moment if the Z94 in Jews is of Semitic, Khazar or some other origin, like, for example, Persian. Someone should look into that.
I've previously outlined my own reasons for saying that the Khazar theory is nonsense:
Some Jews are descendants of Aaron (Kohanim) and Levi (Leviim.) Kohanim and Leviim have different roles in the religion and that status gets handed down from fathers to sons. If all Jews are converts from Khazaria, how did many of them turn into Kohanim and Leviim?

Moreover, there is a continual written record of Jewish legal issues from the Mishna through the rest of the Talmud through the Geonic period, Rishonim and later. If there was an influx of a huge number of converted Jews coming out of Khazaria, it would have engendered many new questions and legal rulings regarding their status as Jews. Where are they?

Not only that, but to get to the level of expert legal knowledge required by leading rabbis is a long educational process. How could a large group of new converts gain such expertise so thoroughly that they could be accepted by the existing Jewish communities without any record of them attending any existing institutions of Jewish study? Jewish law is nothing if not complex.