Population Genetics: Jewish

Exponential growth of Ashkenazi Jews following a Medieval population bottleneck

A recent paper by Marta Costa et al. found that around 80% of Ashkenazi mitochondrial DNA had a prehistoric European origin (and ruled out the Khazar hypothesis). Combined with previous Y chromosome studies indicating that  the male line is Middle Eastern, the results suggested a scenario in which Jewish males married European females after traveling to Europe.

Now another paper, by Shai Carmi et al., reinforces this scenario, finding an “even mix of European and Middle Eastern ancestral populations” (Sequencing an Ashkenazi reference panel supports population-targeted personal genomics and illuminates Jewish and European origins).

The basic picture is illustrated in the following figure.


The left side of the figure at the top shows Ashkenazi origins in the Middle East (AJ=Ashkenazi Jewish), with a bottleneck around 90,000 years ago. Then around 21,000 years ago a portion of the Middle Eastern group migrated to Europe (FL = the Flemish control group) and, according to the authors, became the predominant European group. After undergoing genetic differentiation in Europe (presumably shaping the modern behavioral and intelligence profile of Europeans), there there was an influx of the FL group to the AJ group within Europe, with 49% of Ashkenazi genes coming from the FL. This was followed by an extreme bottleneck around 700 years ago when the Ashkenazi population dwindled to an effective population size of around 330 people. Read more

Jewish population genetics and intelligence revisted

When I reviewed the data on Jewish population genetics for my 1994 book, A People That Shall Dwell Alone, the take home message was that Jews were a Middle Eastern group. But that was before the massive improvements in population genetic methods of recent years. One would think that this would result in a clear picture, but that has not been the case. Data showing a strong Middle Eastern connection was challenged by a paper championing the Khazar hypothesis.

I can’t tell you how many people have sent me emails urging me to endorse the Khazar hypothesis, the logic being that if the Khazar hypothesis is true, then Jews have no biological link to Israel.

But my population genetics guru was quite skeptical about that paper, and now a new paper by Marta Costa et al. puts yet another spin on Ashkenazi origins by finding that around 80% of their mitochondrial DNA has a prehistoric European origin and ruling out the Khazar hypothesis. The new results would likely  indicate that the Ashkenazim would be less Near Eastern and more European, so fans of the Khazar hypothesis may have something to cheer about after all.

Combined with previous Y chromosome studies indicating that  the male line is Middle Eastern, the results suggest a scenario in which Jewish males married European females after traveling to Europe. This has happened elsewhere, as with the Lemba.

This study is getting good reviews, but of course we have to remain open to new findings. Science marches onward.

But taking these results at face value, one might hope that Ashkenazi Jews would feel more kinship with Europe rather than the characteristic posture of hostile outsiders adopted by the organized Jewish community and very common among Ashkenazi Jews generally. But I won’t hold my breath. Such attitudes are far more influenced by social identity processes, which are not sensitive to genetic differences, and according to which Christian Europe is a hated outgroup because of its perceived past history of little more than expulsions and persecution.

Nor do the new findings alter the conception of Judaism as a genetically closed group, with all that implies for an evolutionary analysis of between-group competition. After the original matings in the ancient world, the walls were erected; the new findings indicate very little mtDNA from Eastern Europe. Read more

Who are the Jews?

Legacy: A Genetic History of the Jewish People
Harry Ostrer
Oxford University Press: 2012
288pp., $24.95

Are Jews a religion or race?

This is the age-old question that medical geneticist Harry Ostrer tackles in his concise but informative book, Legacy: A Genetic History of the Jewish People.

As Professor of Pathology and Genetics at Albert Einstein College of Medicine of Yeshiva University and Director of Genetic and Genomic Testing at Montefiore Medical Center, as well as former Director of the Human Genetics Program at New York University’s School of Medicine, Ostrer has devoted much of his career to unraveling the DNA sequencing of recessive genetic disorders common among Jews, such as Tay-Sachs and Gaucher disease. After two decades of medical research, he explains that Jews share more than religious and cultural traditions — a common biological bond links Jews throughout the Diaspora.

This body of work has led Ostrer to conclude that Jews are genetically related worldwide. Three millennia of selective breeding have created a distinct population with unique racial characteristics. Within this broad isolated population, diverse ethnic tribes formed and branched out. Mutual genes serve as the ancestral linkage between major Jewish tribes: Ashkenazi (who are related to one another on average as fifth cousins), Sephardic, Eurasian Khazars, Middle Eastern, and Mizrahi or African Jews.

Legacy is a slim book that incorporates history, natural selection, population genetics, evolutionary psychology, and contemporary medical findings. The author’s quest for the basis of Jewish origins and identity forms the basic storyline of Legacy. Each chapter highlights various aspects of Jewish ancestry: physical measurements and characteristics, DNA studies, blood groupings, genealogical evidence, tribal lineage, physical and psychological traits, and, finally, the crux of Jewish identity. The result is an informative overview of 25 years of detective work unraveling the genetic kinship of Jews. Read more

Review of John Glad’s “Jewish Eugenics”

Jewish Eugenics, by John Glad. Washington, DC: Wooden Shore Publishers, 2011; 464pp. (Downloadable at either www.whatwemaybe or www.woodenshore.org. These sites also have Glad’s Future Human Evolution.)

John Glad begins Jewish Eugenics by noting that “much of what might be termed  ‘accepted eugenics narrative’ is in crass discordance with the historical facts” (p. 8). In other words, we are about to enter one of those academic minefields where “truth” is rigorously cleansed to make sure it is compatible with ethnic interests. Indeed, “writing books about Jews used to be a far easier undertaking than it is today, with Jewish anxieties over ‘anti-Semitism’ having been so elevated as to render dispassionate scholarly discourse nearly impossible” (p. 8).

I am not so sure that dispassionate scholarship is impossible, but it is surely the case that findings that diverge from the self-image desired by any ethnic group will surely be vigorously contested by academic activists or, more probably, consigned to oblivion. Dr. Glad assures me that in his case, it is the latter, writing of his frustration at the silence that has greeted his work. Welcome to the club.

As a university professor, Glad is quite attuned to the politics of having a good career. Critics of eugenics, like the notorious Ashley Montagu (a disciple of Franz Boas), get fat honoraria for delivering superficial, factually challenged lectures sponsored by numerous academic departments and programs. (Glad characterizes a lecture by Montagu as “an impressive demonstration of indoctrination” [p. 91].) On the other hand, those who defend eugenics “are subjected to academic shunning” (p. 91), their books are not used in classes and not purchased by academic libraries. They get no invitations to attend conferences or deliver lectures. Read more

Another Jewish Genetics Paper

Another paper has come out similar to the Atzmon work reviewed in my previous TOO paper.  Having exhaustively examined Atzmon’s study, and seeing that the new Behar work (“The genome-wide structure of the Jewish people“) essentially says the same thing, I’ll keep the comments brief. I have also written the current TOO article (“Jewish Ethnic Genetic Interests“) as a dialogue on the complex topic of how to think about Jewish ethnic interests. Comments on these articles are welcome.

The Dienekes blog does a good job summarizing the paper, so I’ll highlight the major relevant points.

The PCA analysis, a method I view as somewhat weak but with some utility, again shows Ashkenazi and Sephardic Jews as spanning the gulf between European and Middle Eastern populations.  Also see here which includes this figure:

Global “admixture” analysis, similar to Atzmon’s Structure data, shows the Ashkenazi as similar to other Jewish populations (and to Cypriots) and roughly midway between Europeans and groups like Palestinians.  Another view is here.


The regional “admixture” analysis again shows the intermediate nature of Jewish populations and their greater similarity to Middle/Near Easterners than to Europeans.

The link to the original paper’s abstract is here. Note the large proportion of Jewish authors.  Again, these data are essentially produced by Jewish scientists, not by “anti-Semites.”

The authors write:

Most Jewish samples form a remarkably tight subcluster that overlies Druze and Cypriot samples but not samples from other Levantine populations or paired Diaspora host populations.

Therefore, this statement suggests that Jews are not Middle Eastern (“other Levantine populations”) nor European (“paired Diaspora host populations”) but a separate population in between.  However, they seem to be basing that statement on the PCA, which is not reliable.  However, as the “admixture” analysis yields the same “in between” ancestry profile, the statement itself is probably sound.  Note that it mimics Atzmon as well as other previous studies on this topic reviewed here in the past.

The authors also commented thus:

The positioning of the Ashkenazi-Moroccan-Sephardi cluster between contemporary European and Levantine populations is of interest. This intermediate location is not surprising for Ashkenazi Jews, and might intuitively suggest some gene introgression from Central and EastEuropean host populations15. However, the overlapping location of Moroccan and Sephardi Jewish communities should be considered in the context of their historical chronicles. The traditional scenario suggested by historians to explain the establishment of these latter communities is as follows: 1) migration from the Levant to the geographic region corresponding to contemporary Iraq some 2,500 years ago, 2) movement to North Africa during the Arab expansion beginning in the 7th century, 3) movement through Gibraltar to the Iberian Peninsula to merge with and probably overwhelm any small pre-existing Jewish community from the Roman era, 4) expulsion of an estimated greater than one third of the population from the Iberian Peninsula in 1492 (Spain) and 1497 (Portugal) ACE, and 5) re-settlement throughout the then existing North African Jewish communities or establishment of new Jewish communities such as the Turkish and Bulgarian communities under Ottoman rule. Therefore, the clustering of Sephardi and Moroccan Jews is not surprising, but their clustering so tightly with Ashkenazi rather than Middle Eastern (Iran, Iraq) Jews and not with their host populations is surprising. It is also noteworthy that previously reported mtDNA analysis showed that four maternal lineages underwent dramatic expansion as part of the demographic history of Ashkenazi Jews, and these lineages were also found exclusively among Sephardi Jews, but were not present in non-Jewish samples. These results might suggest either shared ancestry prior to the events leading to the generation of these Diaspora communities, or a previously underappreciated level of contact between these communities. An additional scenario might be Central-Eastern European genetic introgression into Ashkenazi Jews and an Iberian-European gene introgression into Sephardi Jews. According to this formulation, a potentially homogeneous European genetic variation would have generated the genetic proximity between the Jewish communities, with the detailed geographic sources within Europe being different.

Note that contra Atzmon, they are looking at the data and speculating about Central/East European admixture. This is a consequence of an over-reliance on PCA which, like Fst, is mindlessly used by populations genetics, over-interpreted, and ends up yielding information of limited usefulness.

What would be better – if it is possible – are “admixture” analyses that could distinguish northwest, southern, central, and eastern European genetic contributions, and then determining how much of each type is present in the Ashkenazim (and Sephardim).  Just looking at placement of groups along a couple of principal components of variation, in a manner which is very context dependent on populations used, cannot determine why a population is where it is.

Further, actual gene sharing analyses (e.g., Atzmon’s IBD analysis) is much more relevant to genetic interests than abstract placements on these graphs.  Even more to the point, higher order genetic structure is not really being considered in these papers.  If it was, I’d suspect greater differentiation between continentally defined groups.

The Atzmon and Behar studies are indeed useful.  But they are, in my opinion, flawed by the conformist tendency of population geneticists to use certain metrics as the foundation of their work when these metrics leave much to be desired.  Do any of these people using Fst for example ever address Jost’s criticisms?

Ted Sallis (email him) writes on scientific issues. 

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Ted Sallis on Jewish genetics

Ted Sallis’s current TOO article makes a number of important points.

First, the fact that Jews are most closely related to Northern Italians does not imply that this was due to conversion in the ancient world. He points out that “the relatively greater similarity of Jews to southern rather than central/eastern Europeans may also to some extent reflect the greater Neolithic ancestry in the southern European groups that is shared by various Jewish groups as one component of their ancestry.”

In other words, the similarity may be due to simple geographic closeness. The similarity may be due to similarities that long pre-date the Jewish Diaspora in the Greco-Roman world of antiquity. This then suggests that my doubts about large-scale conversions to Judaism in the ancient world may be well-founded after all.

Further, the fact that there is very little similarity between Ashkenazi Jews and Eastern and Central Europeans indicates that Ashkenazi Jews remained separate from these populations for hundreds of years.

Sallis also points out that there are technical problems with the PCA analysis — the analysis with the pretty picture showing genetic distances. Such pictures are beguiling and doubtless represent the take-home message for most people. The picture suggests that Ashkenazi Jews (ASH) are more closely related to Northern Italians than to Iranian or Iraqi Jews. But this is not actually the case. In fact, Gil Atzmon explicitly denies it here.

But the IBD (Identical By Descent) analysis provides a very clear picture indicating very close relatedness among Jewish groups. IBD analysis compares gene sequences that are similar or completely identical because they descend from a common ancestor.

As Sallis notes, “this is a strong demonstration of the common origins and very close genetic connections among these groups.” Indeed, twelve of the thirteen comparisons with the highest degree of sharing are between Jewish groups. (The red bars in Part A of the figure represent comparisons of  Jews with other Jewish groups.) This analysis shows that Ashkenazi Jews (ASH in the figure) are substantially more closely related to all other Jewish groups than to any non-Jewish group, including the Northern Italians.

Finally, Sallis makes the important point that

when it comes to Jewish populations and the relatively small genetic distance separating Jews from both Europeans and Middle Easterners, “academics” (particularly Jewish scientists) and the media (as well as Jewish ethnic organizations) have no problem in stressing the genetic uniqueness of Jews and that this uniqueness stamps them as a separate and distinct biological/ethnic entity.However, when it comes to the objectively larger genetic gulf that separates Europeans from, say, Africans or Asians, why, that’s only an “illusion,” there is “no biological basis for race,” “we are all the same,” and “there is more genetic variation within groups than between them.”The contrast in attitude could not be greater.

Indeed, the Forward has an editorial based on the Atzmon et al. article titled “We are one genetically.” They clearly see the data as a wake-up call for Jews to preserve their genetic heritage:

In an age when exclusivity is frowned upon and multiculturalism prized, some Jews may celebrate if the genetic distinctions fade away and are replaced by a more pluralistic definition of who we are — or at least, who our genes say we are. But breaking down the cultural and religious isolation that has characterized Jewish life since ancient times also contains risks. Science tells us that we have, indeed, been one people. Will we remain so?

Well, the only people whose exclusivity is frowned on are White Europeans. But the sad reality is that Jews will continue to attempt to have their cake and eat it too on the issue of concern for genetic continuity as they have on all the other issues related to multiculturalism and Israel: Support for massive non-White immigration and opposition to White identity and interests in America and other Western societies while supporting an ethnonationalist, apartheid state in Israel and taking steps to ensure Jewish genetic continuity in the Diaspora.

Again, it’s worth remembering that a major motivation of the Jabotinsky faction of racial Zionists that now rules Israel was to prevent genetic assimilation that they saw going on the Diaspora. (See Ch. 5 of Separation and Its Discontents, p. 152ff.) They succeeded in their aims.

The ethnonationalist aspirations of Europeans are no less legitimate.

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A new study on Jewish genetics

Kevin MacDonald:  Gil Atzmon and colleagues have come out with the largest study yet comparing Jewish and non-Jewish populations. (See here and here.) Ted Sallis will be coming out with a longer summary for TOO, but I thought I would highlight a couple points.

The study is remarkable for the number of genetic loci studied (3904 SNPs) and the number of people sampled (273 Jews from 7 different Jewish groups (Ashkenazi, Iranian, Syrian, Iraqi, Italian; Greek; Turkish) and 418 people from 16 non-Jewish groups).  As in previous studies, the main message is that Jewish populations do cluster together and are different from the populations they have lived among for hundreds of years.  The 7 Jewish populations divided into a European/Syrian group with a relatively high degree of genetic admixture with European non-Jews (30-60%) and a Middle Eastern group (Iraqi and Iranian Jews). The estimate of 60% overlap between Ashkenazi populations and Europeans indicates that Ashkenazi Jews are an intermediary population with genetic interests that overlap significantly with Europeans.

The new findings were seen as support for the idea that there was significant admixture with non-Jews in Greco-Roman times. This is based on the clustering of the European/Syrian Jews  and the fact that these groups have been separated since ancient times. The authors argue that the data are consistent  with historical accounts of proselytism and large-scale conversions to Judaism in ancient times.  When I reviewed the historical data in A People That Shall Dwell Alone (Ch. 4, pp. 62-78), I ended up rejecting this theory, coming down on the side of historians who doubted how important conversion really was. One thing that convinced me was that there was a lot of evidence for biases against converts. For example, once they converted they were regarded as very undesirable marriage partners and that a pure Jewish genealogy was a very big asset in the marriage market. Families keep their genealogies for generations, and there is a lot of evidence for hostility toward converts. Contrary to Atzmon et al., conversion is not required to explain the large numbers of Jews in the ancient world.

There was also a very pronounced apologetic tone to Jewish advocates of high levels of prosetlytism. But now it looks like they may have been right because the greatest admixture among the European/Syrian groups comes from the Mediterranean area: French, Northern Italian, and Sardinians. It’s hard to see how that could have happened without the admixture occurring in the ancient world. It’s also worth noting that, once again, the data are not compatible with a major role for the Khazars.

In any case, there certainly were elaborate cultural barriers against intermarriage throughout very long stretches of Jewish history, resulting in genetically different populations with substantially different genetic interests. That’s the point of the group evolutionary strategy idea: Admixture would have been much higher without barriers.

And of course, genetic overlap is not the same thing as a psychological sense of common interest. Following John Murray Cuddihy, I have often stressed the hostility and sense of historical grievance that Jews have had toward the Europeans they have lived among for centuries. Psychological attitudes do not necessarily match up one-to-one with genetic distance. Attitudes are affected not only by genetic similarity but are at least partly affected by ingroup/outgroup psychology which is known to be fairly insensitive to genetic distance: People can develop great hatreds toward the fans of different football teams.

The point is that it’s quite possible that Jewish hostility toward Europeans and their culture is not really warranted by the recent findings on genetic distance–an intriguing possibility to say the least.

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