Genetic studies on Jews

Genetic studies on the Jews are part of population genetics. This discipline is used to better understand the chronology of migration and thus complements the results provided by history, archeology, language or paleontology. The interest of these studies is to investigate the origins of various Jewish populations today. In particular, they investigate whether there is a common genetic heritage among various Jewish populations.

Background

Since the 1970s, many studies have attempted to determine whether, despite the complex history of migrations, common ancestors existed to the present Jewish communities or if the descendants are related instead to the non-Jewish populations where they lived. The earlier studies tried to answer this question using "classic" genetic markers (blood groups, enzymes, etc.).[1] Contradictory answers were given according to locus used.[2] One explanation for these contradictions is that the variations associated with a locus are influenced by natural selection.[2] Since the late 1980s and especially since the beginning of the century, geneticists have worked on analysis of the Y chromosome (transmitted from father to son) and mitochondrial DNA (transmitted from mother to child), which have the characteristic to be transmitted in full (without recombination). It is possible to trace the common direct-line ancestral populations of various peoples of the world. Recent studies have been conducted on a large number of genes homologous chromosomes or autosomes (all chromosomes except chromosomes X and Y).. A 2009 study was able to genetically identify individuals with full or partial Ashkenazi Jewish ancestry.[3] In August 2012, Dr. Harry Ostrer in his book Legacy: A Genetic History of the Jewish People, summarized his and other work in genetics of the last 20 years, and concluded that all major Jewish groups share a common Middle Eastern origin. Ostrer also claimed to have refuted any large-scale genetic contribution from the Turkic Khazars.[4][unreliable source?]Citing Autosomal DNA studies, Nicholas Wade estimates that "Ashkenazic and Sephardic Jews have roughly 30 percent European ancestry, with most of the rest from the Middle East." He further noticed that "The two communities seem very similar to each other genetically, which is unexpected because they have been separated for so long." Concerning this relationship he points to Atzmon conclusions that "the shared genetic elements suggest that members of any Jewish community are related to one another as closely as are fourth or fifth cousins in a large population, which is about 10 times higher than the relationship between two people chosen at random off the streets of New York City"[5] Concerning North African Jews, Autosomal genetic analysis in 2012 revealed that North African Jews are genetically close to European Jews. This findings "shows that North African Jews date to biblical-era Israel, and are not largely the descendants of natives who converted to Judaism,"[6]


Y DNA studies examine various paternal lineages of modern Jewish populations. Such studies tend to imply a small number of founders in an old population whose members parted and followed different migration paths.[2] In most Jewish populations, these male line ancestors appear to have been mainly Middle Eastern. For example, Ashkenazi Jews share more common paternal lineages with other Jewish and Middle Eastern groups than with non-Jewish populations in areas where Jews lived in Eastern Europe, Germany and the French Rhine Valley. This is consistent with Jewish traditions in placing most Jewish paternal origins in the region of the Middle East.[7][8]

The maternal lineages of Jewish populations, studied by looking at mitochondrial DNA, are generally more heterogeneous.[9] Scholars such as Harry Ostrer and Raphael Falk believe this indicates that many Jewish males found new mates from European and other communities in the places where they migrated in the diaspora after fleeing ancient Israel.[10] Behar et al. in 2008 published evidence suggesting that about 40% of Ashkenazi Jews originate maternally from just four female founders, who were of Middle Eastern origin, while the populations of Sephardi and Mizrahi Jewish communities "showed no evidence for a narrow founder effect".[9] Evidence for female founders has been observed in other Jewish populations. With the exception of Ethiopian and Indian Jews, it has been argued that all of the Jewish populations have mitochondrial genomes that were of Middle Eastern origin.[11][12]In 2013, Richards et al. to the contrary published work suggesting that an estimated "80 percent of Ashkenazi maternal ancestry comes from women indigenous to Europe, and 8 percent from the Near East, with the rest uncertain".[13] Apparently, in this case, Jewish males migrated to Europe and took new wives from the local population, and converted them to Judaism.

Studies of autosomal DNA, which look at the entire DNA mixture, have become increasingly important as the technology develops. They show that Jewish populations have tended to form relatively closely related groups in independent communities, with most in a community sharing significant ancestry in common.[14] For Jewish populations of the diaspora, the genetic composition of Ashkenazi, Sephardi, and Mizrahi Jewish populations show a predominant amount of shared Middle Eastern ancestry. According to Behar, the most parsimonious explanation for this shared Middle Eastern ancestry is that it is "consistent with the historical formulation of the Jewish people as descending from ancient Hebrew and Israelite residents of the Levant" and "the dispersion of the people of ancient Israel throughout the Old World".[15] North African, Italian and others of Iberian origin show variable frequencies of admixture with non-Jewish historical host populations among the maternal lines. In the case of Ashkenazi and Sephardi Jews (in particular Moroccan Jews), who are apparently closely related, the non-Jewish component is mainly southern European. Behar et al. have remarked on an especially close relationship to modern Italians.[16][17] The studies show that the Bene Israel and Black Cochin Jews of India, Beta Israel of Ethiopia, and a portion of the Lemba people of southern Africa, while more closely resembling the local populations of their native countries, have some ancient Jewish descent.[12][18][19][20]

Paternal lineage, Y chromosome

In 1992 G. Lucotte and F. David were the first genetic researchers to have documented a common paternal genetic heritage between Sephardi and Ashkenazi Jews.[21][22] In 1993, A. S. Santachiara Benerecetti, et al. have suggested the Middle Eastern origin of Jewish paternal lineages.[23]

In 2000, M. Hammer, et al. conducted a study on 1371 men and definitively established that part of the paternal gene pool of Jewish communities in Europe, North Africa and Middle East came from a common Middle East ancestral population. They suggested that most Jewish communities in the Diaspora remained relatively isolated and endogamous compared to non-Jewish neighbor populations.[2][12][24]

In a study of Israeli and Palestinian Muslim Arabs, more than 70% of the Jewish men and 82% of the Arab men whose DNA was studied, had inherited their Y chromosomes from the same paternal ancestors, who lived in the region within the last few thousand years. "Our recent study of high-resolution microsatellite haplotypes demonstrated that a substantial portion of Y chromosomes of Jews (70%) and of Palestinian Muslim Arabs (82%) belonged to the same chromosome pool."[25] In relation to the region of the Fertile Crescent, the same study noted; "In comparison with data available from other relevant populations in the region, Jews were found to be more closely related to groups in the north of the Fertile Crescent (Kurds, Turks, and Armenians) than to their Arab neighbors."[26]

Approximately 35% to 43% of Jewish men are in the paternal line known as haplogroup J[Note 1] and its sub-haplogroups. This Haplogroup is particularly present in the Middle East, Southern Europe, and Northern Africa.[27] Fifteen to 30% are in haplogroup E1b1b[Note 2], (or E-M35) and its sub-haplogroups.

Y-DNA of Ashkenazi Jews

The term "Ashkenazi" is relatively well defined in these studies; it refers to Jews living or whose "paternal" ancestors immigrated to the following parts of central and eastern Europe: the Rhine Valley, France, Germany, the Netherlands, Austria, Hungary, former Czechoslovakia, Belarus, Lithuania, Poland, Romania, Russia, and Ukraine. This excludes the Jews of southern Europe (Balkans, Iberia and Italy). Non Jews in the latter areas are outside the definitions used for estimating the genetic make-up of the ancestral "neighbor" or "host" populations of Ashkenazim.

All relevant Y-DNA studies have concluded that the majority of the paternal genetic heritage among Ashkenazim and other Jewish communities is similar to those found dominating Middle Eastern populations, and probably originated there. A smaller but still significant part of the Ashkenazi male-line population is more likely to have originated from European populations.

A study of haplotypes of the Y chromosome, published in 2000, addressed the paternal origins of Ashkenazi Jews. Hammer et al.[29] confirmed that the Y chromosome of most Ashkenazi and Sephardi Jews contained mutations that are also common among Middle Eastern peoples, but uncommon in the general European population. This suggested that the male ancestors of the Ashkenazi Jews could be traced mostly to the Middle East. The proportion of male genetic admixture in Ashkenazi Jews amounts to less than 0.5% per generation over an estimated 80 generations, with "relatively minor contribution of European Y chromosomes to the Ashkenazim," and a total admixture estimate "very similar to Motulsky's average estimate of 12.5%." However, when all haplotypes were included in the analysis, the admixture percentage increased to 23% ± 7%.[Note 3] Hammer et al. add that "Diaspora Jews from Europe, Northwest Africa, and the Near East resemble each other more closely than they resemble their non-Jewish neighbors." In addition, the non-Jewish components in Ashkenazim and Sephardim are generally South European, specifically Greek.

The frequency of haplogroup R1b in the Ashkenazim population is similar to the frequency of R1b in Middle Eastern populations. Given that haplogroup R1b is particularly abundant in populations of Western Europe, studies of Nebel et al. (2001) and Behar et al. (2004)[30] suggest some Western European contribution to those ~10% of R1b found among Ashkenazim. The Behar et al. large 2004 study of Ashkenazi Jews records a percentage of 5% - 8% European contribution to the Ashkenazi gene pool.[Note 4] In the words of Behar:

Because haplogroups R-M17 (R1a) and R-P25 (R1b) are present in non-Ashkenazi Jewish populations (e.g., at 4% and 10%, respectively) and in non-Jewish Near Eastern populations (e.g., at 7% and 11%, respectively; Hammer et al. 2000; Nebel et al. 2001), it is likely that they were also present at low frequency in the AJ founding population. The admixture analysis shown in Table 6 suggests that 5%–8% of the Ashkenazi gene pool is, indeed, comprised of Y chromosomes that may have introgressed from non-Jewish European populations.

For G. Lucotte et al.,[31] the R1b frequency is about 11%.[Note 5] In 2004, When the calculation is made excluding Jews from Netherlands the R1b rate is 5% ± 11.6%.[30]

Two studies by Nebel et al. in 2001 and 2005, based on Y chromosome polymorphic markers, showed that Ashkenazi Jews are more closely related to other Jewish and Middle Eastern groups than to their host populations in Europe (defined in the using Eastern European, German, and French Rhine Valley populations). However, 11.5% of male Ashkenazim were found to belong to R1a1a (R-M17), the dominant Y chromosome haplogroup in Eastern European populations. They hypothesized that these chromosomes could reflect low-level gene flow from surrounding Eastern European populations, or, alternatively, that both the Ashkenazi Jews with R1a1a (R-M17), and to a much greater extent Eastern European populations in general, might partly be descendants of Khazars. They concluded "However, if the R1a1a (R-M17) chromosomes in Ashkenazi Jews do indeed represent the vestiges of the mysterious Khazars then, according to our data, this contribution was limited to either a single founder or a few closely related men, and does not exceed ~12% of the present-day Ashkenazim.".[7][32] This hypothesis is also supported by the D. Goldstein in his book Jacob's legacy: A genetic view of Jewish history.[33] However, Faerman (2008) states that "External low-level gene flow of possible Eastern European origin has been shown in Ashkenazim but no evidence of a hypothetical Khazars' contribution to the Ashkenazi gene pool has ever been found.".[34]

Furthermore, 7%[30][35] of Ashkenazi have the haplogroup G2c, which is extremely rare in the rest of the human population. It seems to be present in a small percentage in the Pashtuns in Afghanistan but the origin of this haplogroup is unknown. The haplogroup Q1b (Q-M378) is also rare in the rest of the human population. It is found in Hazara and Sindhi[36] which are two nomadic tribes in Pakistan. It is also found in the Uyghurs of North-Western China.[37] Behar et al. suggest that those haplogroups are minor Ashkenazi Jews founding lineages.[30]

Among Ashkenazi Jews, Jews of Netherlands seem to have a particular haplogroups distribution since nearly one quarter of them have the Haplogroup R1b1 (R-P25), in particular sub-haplogroup R1b1b2 (R-M269), which is characteristic of Western European populations.[30]

Ashkenazi men show low Y-DNA diversity within each major haplogroup, meaning that compared to the size of the modern population, it seems there were once a relatively small number of men having children. This possibly results from a series of founder events and high rates of endogamy within Europe. Despite Ashkenazi Jews representing a recently founded population in Europe, founding effects suggest that they probably derived from a large and diverse ancestral source population in the Middle East, who may have been larger than the source population from which the indigenous Europeans derived.[30]

Haplogroup distribution among Ashkenazim
E1b1b1 (M35) G (M201) J1 or J* (12f2b) J2 (M172) Q1 (P36) R1a1a (M17) R1b1 (P25)
Sample number E1b1b1a (M78) E1b1b1c (M123) G2c (M377) J1 (M267) J* J2a* (M410) J2a1b (M67) Q1b (M378) R1b1b2 (M269) R1b1* (P25)
Hammer 2009 [35] large[Note 6] ~3% ~17% ~7% ~17% ~6% ~14% ~7% Not given ~9% ~2%
Behar 2004 [30] 442 16.1% 7.7% 19% 19% 5.2% 7.5% 10%
Semino 2004[27] ~80 5.2% 11.7% Not tested 14.6% 12.2% 9.8% Not tested Not tested Not tested
Nebel 2001[7] 79 23%  ? 24% 19%  ? 12.7% 11.4%
Shen 2004[38] 20 10% 10% 5% 20% 5% 15% 5% 20% 10%

Y-DNA of Sephardi Jews

The term "Sephardi" refers to significantly different populations from one study to another. It can have a very restrictive meaning and only referring to people speaking Judeo-Spanish (excluding Moroccan Jews) or at the opposite the term Sephardi may designate all non-Ashkenazi populations (excluding Jews from Ethiopia, Yemen and the Kurdish Jews). Between these two extremes, all kinds of variations exist.

Investigations made by Nebel et al.[7] on the genetic relationships among Ashkenazi Jews, Kurdish and Sephardi (North Africa, Turkey, Iberian Peninsula, Iraq and Syria) indicate that Jews are more genetically similar to groups in northern Fertile Crescent (Kurds, Turks and Armenians) than to Arabs. Considering the timing of this origin, the study found that "the common genetic Middle Eastern background (of Jewish populations ) predates the ethnogenesis in the region and concludes that the Y chromosome pool of Jews is an integral part of the genetic landscape of Middle East.[7]

Y-DNA of Jews from North Africa

The largest study to date on the Jews of North Africa has been led by Gerard Lucotte et al. in 2003.[31] This study showed that the Jews of North Africa[Note 7] showed frequencies of their paternal haplotypes almost equal to those of the Lebanese and Palestinian non-Jews.

The authors also compared the distribution of haplotypes of Jews from North Africa with Sephardi Jews and Ashkenazi Jews and found a common origin between these groups.[39] The Jewish community of the island of Djerba in Tunisia is of special interest, making the tradition back to the time of the destruction of the First Temple. Two studies have attempted to test this hypothesis first by G. Lucotte et al. from 1993,[40] the second of F. Manni et al. of 2005.[41] They also conclude that the Jews of Djerba's paternal gene pool is different from the Arabs and Berbers of the island. For the first 77.5% of samples tested are of haplotype VIII (probably similar to the J haplogroup according Lucotte), the second shows that 100% of the samples are of Haplogroup J *. The second suggests that it is unlikely that the majority of this community comes from an ancient colonization of the island while for Lucotte it is unclear whether this high frequency is really an ancient relationship.

These studies therefore suggest that the paternal lineage of North African Jews comes predominantly from the Middle East with a minority contribution of African lineages, probably Berbers.

Y-DNA of Portuguese Jews

A recent study by Inês Nogueiro et al. (July 2009) on the Jews of north-eastern Portugal (region of Trás-os-Montes) showed that their paternal lines consisted of 35.2% lineages more typical of Europe (R : 31.7%, I : 3.5% ), and 37% lineages more typical of the Near East (J1: 12%, J2-M172: 25% ) and consequently, the Portuguese Jews of this region were genetically closer to other Jewish populations than to Portuguese non-Jews.[42]

N E-M78 E-M81 E-M34 G I J1 J2 T R1a R1b1b1 R1b1b1b2
57 3.5% 5.2% 0% 3.5% 3.5% 12.3% 24.5% 15.8% 1.8% 1.8% 28.1%

Y-DNA of Oriental Jews

Lucotte et al. 2003 study found that (Oriental, Sephardic, Ashkenazic Jews and Lebanese and Palestinians), "seem to be similar in their Y-haplotype patterns, both with regard to the haplotype distributions and the ancestral haplotype VIII frequencies." The authors stated in their findings that these results confirm similarities in the Y-haplotype frequencies of this Near-Eastern populations, sharing a common geographic origin."[43]

Y-DNA of Roman Jews

Hammer et al.[2] maintained that the paternal lines of Roman Jews were close to those of Ashkenazi Jews. They also claim that these mostly originated from the Middle East.

Y-DNA of Kurdish Jews

In the article by Nebel et al.[7] the authors show that Kurdish and Sephardi Jews have paternal genetic heritage indistinguishable. The study shows that mixtures between Kurdish Jews and their Muslim hosts are negligible and that Kurdish Jews are closer to other Jewish groups than to their long term host population. Mr. Hammer[2] had already shown the strong correlation between the genetic heritage of Jews from North Africa with Kurdish Jews.

Y-DNA of the Jews of Yemen

The studies of Shen[38] and Hammer et al.[2] show that the paternal genes of Yemenite Jews is similar to that of other Jewish populations.

Y-DNA of Jews from Ethiopia

A study of [44] Lucotte and Smets has shown that the genetic father of Beta Israel (Ethiopian Jews) was close to the Ethiopian non-Jewish populations. This is consistent with the theory that Beta Israel are descendants of ancient inhabitants of Ethiopia, not the Middle East.

Hammer et al. in 2000[2] and the team of Shen in 2004[38] arrive at similar conclusions, namely a genetic differentiation in – other people in the north of Ethiopia, which probably indicates a conversion of local populations.

A 2010 study by Behar et al. on the Genome-wide structure of Jews observed that the Beta Israel had similar levels of the Middle Eastern genetic clusters as the Semitic-speaking Tigreans and Amharas. However, compared to the Cushitic-speaking Oromos, who are the largest ethnic group in Ethiopia, the Beta Israel had higher levels of Middle Eastern admixture.

A 2012 study showed that while primarily related to the local populations, Ethiopian Jews have very distant genetic links to the Middle East from some 2,000 years ago, and are likely descended from a few Jewish founders. It has been speculated that the community began when a few itinerant Jews who settled in Ethiopia in ancient times, converted locals to Judaism, and married into the local populations.[20]

Priestly Families

Cohanim

Nephrologist Dr. Karl Skorecki decided to analyze the Cohanim to see if they were the descendants of one man, in which case they should have a set of common genetic markers.

To test this hypothesis, he contacted Dr. Michael Hammer of the University of Arizona, a researcher in molecular genetics and a pioneer in research on chromosome.[45] Their article, published in Nature in 1997, has had some impact. A set of special markers (called Cohen Modal Haplotype or CMH) was defined as one which is more likely to be present in the Cohanim, defined as contemporary Jews named Cohen or a derivative, and it was proposed that this results from a common descent from the ancient priestly lineage than from the Jewish population in general.

But, subsequent studies[46] showed that the number of genetic markers used and the number of samples (of people saying Cohen) were not big enough. The last study, conducted in 2009 by Hammer and Behar et al.,[35] says 20 of the 21 Cohen haplogroups have no single common haplogroup; five haplogroups comprise 79.5% of all haplogroups of Cohen. Among these first 5 haplogroups, J-P58 * (or J1E) accounts for 46.1% of Cohen and the second major haplogroup, J-M410 or J2am accounts for 14.4%. Hammer and Behar have redefined an extended MHC haplotype as determined by a set of 12 markers and having as "background" haplogroup determining the most important lines J1E (46.1%). This haplotype is absent among non-Jews in 2099 analyzed in the study. It appeared there would be a 3000 ± 1000 years. This study nevertheless confirms that the current Cohen descended from a small number of paternal ancestors. In the summary of their findings the authors concluded that " Our estimates of the coalescence time also lend support to the hypothesis that the extended CMH represents a unique founding lineage of the ancient Hebrews that has been paternally inherited along with the Jewish priesthood."[47]

Levites

A 2003 study of the Y-chromosome by Behar et al. points to multiple origins for Ashkenazi Levites, a priestly class who comprise approximately 4% of Ashkenazi Jews. It found that Haplogroup R1a1a (R-M17), which is uncommon in the Middle East or among Sephardi Jews, but dominant in Eastern Europe, is present in over 50% of Ashkenazi Levites, while the rest of Ashkenazi Levites' paternal lineage is of apparent Middle Eastern origin. Behar suggested a founding event, probably involving one or very few European men, occurring at a time close to the initial formation and settlement of the Ashkenazi community as a possible explanation.[48] Nebel, Behar and Goldstein speculate that this may indicate a Khazar origin.[33]

Maternal line: Mitochondrial DNA

Studies of mitochondrial DNA of Jewish populations are more recent and are still debatable. However, it seems that there are no maternal lines common to all Jewish people.[9][Note 8] Until 2006, geneticists attributed most often the origin of Jewish populations to male individuals who emigrated from the Middle East and took women as wives in the indigenous populations, who later converted to Judaism.[10] D.M. Behar, et al. published a study in 2008 that tried to review this assertion.[49]

According to M.G. Thomas, et al. in 2002, a number of Jewish communities reveal direct-line maternal ancestry originating from a few women. This was seen in independently founded communities in different geographic areas. What they shared was limited genetic additions later on the female side. Together, this is described as the founder effect. Those same communities had diversity in the male lines that was similar to the non-Jewish population.[50]

Reflecting on previous mtDNA studies, carried out by Behar, Atzmon and al concludes that all major Jewish population groups are showing evidence for founder females of Middle Eastern origin with coalescence times >2000 years[11]

Mt-DNA of Ashkenazi Jews

A 2006 study by Behar et al.,[51] based on high-resolution analysis of Haplogroup K(mtDNA), suggested that about 40% of the current Ashkenazi population is descended matrilineally from just four women, or "founder lineages", that were "likely from a Hebrew/Levantine mtDNA pool" originating in the Middle East in the 1st and 2nd centuries CE. Moreover, a maternal line "sister" was found among the Jews of Portugal, North Africa, France, and Italy. They wrote:

Both the extent and location of the maternal ancestral deme from which the Ashkenazi Jewry arose remain obscure. Here, using complete sequences of the maternally inherited mitochondrial DNA (mtDNA), we show that close to one-half of Ashkenazi Jews, estimated at 8,000,000 people, can be traced back to only four women carrying distinct mtDNAs that are virtually absent in other populations, with the important exception of low frequencies among non-Ashkenazi Jews. We conclude that four founding mtDNAs, likely of Near Eastern ancestry, underwent major expansion(s) in Europe within the past millennium...[51][12]

A 2007 study by J. Feder et al.[52] confirms the hypothesis of the founding of non-local origin among the maternal lines. Their study did not address the geographical origin of Ashkenazim and therefore does not explicitly confirm the origin "Levantine" of these founders. This study revealed a significant divergence in total haplogroup distribution between the Ashkenazi Jewish populations and their European host populations, namely Russians, Poles and Germans. They concluded that, regarding mtDNAs, the differences between Jews and non-Jews are far larger than those observed among the Jewish communities. The study also found that "the differences between the Jewish communities can be overlooked when non-Jews are included in the comparisons." It supported previous interpretations of "little or no gene flow from the local non-Jewish communities in Poland and Russia to the Jewish communities in these countries."[53]

Considering Ashkenazi Jews, Atzmon (citing Behar above) states that beyond four founder mitochondrial haplogroups of Middle Eastern origins which comprise approximately 40% of Ashkenazi Jewish mtDNA, the remainder of the mtDNA falls into other haplogroups, many of European origin. He further noticed that beyond Ashkenazi Jews, "Evidence for founder females of Middle Eastern origin has been observed in other Jewish populations based on non overlapping mitochondrial haplotypes with coalescence times >2000 years"[11]

A study at the University of Huddersfield led by Professor Martin B. Richards, the results of which were released in October 2013, analyzed about 2,500 complete and 28,000 partial Mt-DNA genomes of mostly non-Jews, and 836 partial Mt-DNA genomes of Ashkenazi Jews. The study concluded that 65%-81% of Ashkenazi Mt-DNA is European in origin, claiming that all four founding mothers were European, and that most of the remaining lineages are also European. The study claims that only 8% of Ashkenazi Mt-DNA is Middle Eastern in origin, and the origin of the rest is unclear. They wrote:

If we allow for the possibility that K1a9 and N1b2 might have a Near Eastern source, then we can estimate the overall fraction of European maternal ancestry at ~65%. Given the strength of the case for even these founders having a European source, however, our best estimate is to assign ~81% of Ashkenazi lineages to a European source, ~8% to the Near East and ~1% further to the east in Asia, with ~10% remaining ambiguous... Thus at least two-thirds and most likely more than four-fifths of Ashkenazi maternal lineages have a European ancestry.[54]

Regarding the origin of Ashkenazi admixture the analyses suggest that "the first major wave of assimilation probably took place in Mediterranean Europe, most likely in the Italian peninsula with substantial further assimilation of minor founders in west/central Europe." The authors found "less evidence for assimilation in Eastern Europe, and almost none for a source in the North Caucasus/Chuvashia, as would be predicted by the Khazar hypothesis" The study was criticized by geneticist Doron Behar, who stated that while the Mt-DNA of Ashkenazi Jews is of mixed Middle Eastern and European origins, the deepest maternal roots of Ashkenazi Jews are not European. Harry Ostrer said Richards' study seemed reasonable, and corresponded to the known facts of Jewish history. Karl Skorecki of the Rambam Health Care Campus stated that there were serious flaws of phylogenetic analysis.[55] Both Behar and Skorecki claim that the Mt-DNA used in the study did not represent the full spectrum of mitochondrial diversity. Eran Elhaik, a research associate studying genetics at the Johns Hopkins University School of Public Health, argues that the evidence ruled out a Near Eastern origin for many Ashkenazi mitochondrial lineages but challenged the conclusion that a Khazarian contribution is absent. David B. Goldstein, the Duke University geneticist who first found similarities between the founding mothers of Ashkenazi Jewry and European populations, said that although Richards' analysis was well-done, and 'could be right'[55] the estimate that 80% of Ashkenazi Jewish Mt-DNA is European was not statistically justified given the random rise and fall of mitochondrial DNA lineages. Geneticist Antonio Torroni of the University of Pavia found the conclusions very convincing, adding that recent studies of cell nucleus DNA also show “a very close similarity between Ashkenazi Jews and Italians".[56][57][58][59]

Mt-DNA of Jews from North Africa

Analysis of mitochondrial DNA of the Jewish populations of North Africa (Morocco, Tunisia, Libya) has been the subject of further detailed study in 2008 by Doron Behar et al.[49] It shows that Jews from this region do not share the haplogroups of the mitochondrial DNA haplogroups (M1 and U6), which are typical of the North African of Berber and Arab populations. Similarly, while the frequency of haplogroups L, associated with sub-Saharan Africa, are around an average of 20–25% at the Berber populations studied, it is only 1.3%, 2.7% and 3.6% respectively among Jews from Morocco, Tunisia and Libya.[9]

Behar et al. conclude that it is unlikely that North African Jews have significant Arab, or Berber admixture, "consistent with social restrictions imposed by religious restrictions," or endogamy. This study also found genetic similarities between the Ashkenazi and North African Jewish mitochondrial DNA pools, but differences between both of these of the diaspora and Jews from the Middle East. The study found that about 40% of Libya's Jews are descendants of one woman along their maternal lines and that 43% of Tunisian Jews descended from four women along their maternal lines.[60]

Mt-DNA of Jews from the Iberian Peninsula

The data (mt-DNA) recovered by D. Behar et al. are located in the village of Belmonte in Portugal in a community descended from crypto-Jews. It is not possible to generalize the entire Iberian Peninsula.

Mt-DNA of Jews from Ethiopia

The results are similar to those of the male population, namely, genetic characteristics identical to those of surrounding populations.[50]

Mt-DNA of the Jews of Turkey

Mt-DNA of the Jews of Turkey is extremely divergent,[49] which means that the genetic mother is from very different origins. It is interesting to note that an Iberian-type lineage has been found, which is consistent with historical data, that is, the expulsion of Jews from the Iberian Peninsula.[Note 9]

Mt-DNA of the Jews of Georgia

According to the study of G. Thomas et al., 51% of Georgian Jews are descended from a single female.[50] (Behard holds that 58% are descended from the female ancestor.[49]). Researchers have not determined the origin of this lineage.

Mt-DNA of Jews from Yemen

In a study by Richards et al., authors suggest that a minor proportion of haplogroup L1 and L3A lineage from sub-Saharan Africa is present among Jews from Yemen. However, these lines are 4 times smaller in proportion than among non-Jewish Yemenis.[61] These sub-Saharan haplogroups are virtually absent among Jews from Iraq, Iran and Georgia and do not appear among Ashkenazi Jews.[61]

The Jewish population of Yemen also reveals a founder effect. 42% of the direct maternal lines are traced to five women, four originating in western Asia, and one in sub-Saharan Africa.[49]

Mt-DNA of Cochin Jews and of Bene Israel Indian subcontinent

According to the study of 2008 b D. Behar et al., the maternal lineage of the Jews of India has a local origin for the vast majority of the community. The maternal gene pool also includes some minor maternal lineage originating in the area of Iraq/Iran or Italy.[49] However, for the Bene Israel, their paternal lineage indicates Middle Eastern ancestry.[19] Black Cochin Jews also have genetic similarities with other Jews, in particular with Yemenite Jews, along with the indigenous populations of India.[62]

Autosomal DNA

These studies focus upon autosomal chromosomes, the 22 homologous or autosomes (non sex chromosomes), rather than on the paternal or maternal lines. The technology has changed rapidly and so older studies are different in quality to newer ones.

An initial study[63] conducted in 2001 by N. Rosenberg et al. on six Jewish populations (Poland, Libya, Ethiopia, Iraq, Morocco, Yemen) and two non-Jewish populations (Palestinians and Druze) showed that while the eight groups are close, the Jews of Libya have a genetic signature separate from their genetic isolation and a possible combination with Berber populations.[Note 10] This same study suggested a close relationship between Jews of Yemen and those of Ethiopia.

A 2006 study by Seldin et al. used over five thousand autosomal SNPs to demonstrate European genetic substructure. The results showed "a consistent and reproducible distinction between 'northern' and 'southern' European population groups". Most northern, central, and eastern Europeans (Finns, Swedes, English, Irish, Germans, and Ukrainians) showed >90% in the 'northern' population group, while most individual participants with southern European ancestry (Italians, Greeks, Portuguese, Spaniards) showed >85% in the 'southern' group. Both Ashkenazi Jews as well as Sephardic Jews showed >85% membership in the "southern" group. Referring to the Jews clustering with southern Europeans, the authors state the results were "consistent with a later Mediterranean origin of these ethnic groups".[64]

A 2007 study by Bauchet et al. found that Ashkenazi Jews were most closely clustered with Arabic North African populations when compared to the global population of that study, and in the European structure analysis, they share genetic similarities with Greeks and Southern Italians, reflecting their east Mediterranean origins.[65]

In a 2009 study by Kopelman et al., four Jewish groups, Ashkenazi, Turkish, Moroccan and Tunisian, were found to share a common origin from the Middle East, with more recent admixture that has resulted in "intermediate placement of the Jewish populations compared to European and Middle Eastern populations". The authors found that the "most similar to the Jewish populations is the Palestinian population". The Tunisian Jews were found to be distinct from three other Jewish populations, which might tend to suggest, according to the authors, a greater genetic isolation and/or a significant contribution of local Berber as in the case of Libyan Jews. Concerning the theory of Khazar ancestry in Ashkenazi, the authors found no direct evidence. On the one hand they detected a genetic similarity between Jewish populations in the study, especially Ashkenazi, and the Adyghe people (a group from the Caucasus, whose region was formerly occupied by the Khazars). On the other hand, the Adyghe themselves, living on the edge of geographical Europe, clustered more closely than other European populations to Middle Easterners including Palestinians, Bedouin, and non-Ashkenazi Jews.[12][66]

Another study of L. Hao et al. (October 2009)[67] studied seven groups of Jewish populations with different geographic origin (Ashkenazi, Italians, Greeks, Turks, Iranians, Iraqis and Syrians) and showed that the individuals all shared a Middle Eastern background in common, although they were also genetically distinguishable from each other. In public comments, Harry Ostrer, the director of the Human Genetics Program at NYU Langone Medical Center, and one of the author of this study, concluded "We have shown that Jewishness can be identified through genetic analysis, so the notion of a Jewish people is plausible."[68]

A genome-wide genetic study carried out by Need et al. and published in 2009 showed that "individuals with full Jewish ancestry formed a clearly distinct cluster from those individuals with no Jewish ancestry." The study found that the Jewish cluster examined, fell between that of Middle Eastern and European populations. Reflecting on this findings the authors concluded that "It is clear that the genomes of individuals with full Ashkenazi Jewish ancestry carry an unambiguous signature of their Jewish heritage, and this seems more likely to be due to their specific Middle Eastern ancestry than to inbreeding."[69]

Autosomal genetic distances (Fst) based on SNPs in Tian et al. (2009)[70][71]
Italians Greeks Spanish Germans Druze Palestinians Irish Russians
Ashkenazi 0.0040 0.0042 0.0056 0.0072 0.0088 0.0093 0.0109 0.0137

In June 2010, Behar et al. "shows that most Jewish samples form a remarkably tight subcluster with common genetic origin, that overlies Druze and Cypriot samples but not samples from other Levantine populations or paired Diaspora host populations. In contrast, Ethiopian Jews (Beta Israel) and Indian Jews (Bene Israel and Cochini) cluster with neighboring autochthonous populations in Ethiopia and western India, respectively, despite a clear paternal link between the Bene Israel and the Levant.".[16][5] "The most parsimonious explanation for these observations is a common genetic origin, which is consistent with an historical formulation of the Jewish people as descending from ancient Hebrew and Israelite residents of the Levant." In conclusion the authors are stating that the genetic results are concordant "with the dispersion of the people of ancient Israel throughout the Old World". Regarding the samples he used Behar points out that "Our conclusion favoring common ancestry (of Jewish people) over recent admixture is further supported by the fact that our sample contains individuals that are known not to be admixed in the most recent one or two generations."

In July 2010, Bray et al., using SNP microarray techniques and linkage analysis,[72] "confirms that there is a closer relationship between the Ashkenazim and several European populations (Tuscans, Italians, and French) than between the Ashkenazim and Middle Eastern populations" and that European "admixture is considerably higher than previous estimates by studies that used the Y chromosome" adding that their study "support the model of a Middle Eastern origin of the Ashkenazim population followed by subsequent admixture with host Europeans or populations more similar to Europeans" and that their data imply that modern Ashkenazi Jews are perhaps even more similar with Europeans than modern Middle Easterners. The level of admixture with European population was estimated between 35 to 55%. The study assumed Druze and Palestinian Arabs populations to represent the reference to world Jewry ancestor genome. With this reference point, the linkage disequilibrium in the Ashkenazi Jewish population was interpreted as "matches signs of interbreeding or 'admixture' between Middle Eastern and European populations". Also, in their press release, Bray stated: "We were surprised to find evidence that Ashkenazi Jews have higher heterozygosity than Europeans, contradicting the widely-held presumption that they have been a largely isolated group". Nevertheless, the authors indicated that possible Achilles' heel for their conclusions is that their calculations might have "overestimated the level of admixture" in case that the true Jewish ancestors were genetically closer to Southern Europeans than Druze and Palestinian Arabs are and predicted that using the non Ashkenazi Jewish Diaspora populations as reference for world Jewry ancestor genome would "underestimate the level of admixture", since they find it reasonable that the non Ashkenazi Jewish Diaspora has also "undergone the similar admixture" compared to Ashkenazi Jews.[73][74]

Zoossmann-Diskin (2010) argues, that based upon X chromosome and autosomal DNA chromosomes, Eastern European Jewish populations and Jewish populations from Iran, Iraq and Yemen, do not have the same genetic origins. In particular, concerning Eastern European Jews, he believes the evidence points to a dominant amount of southern European, and specifically Italian, ancestry, which he argues is probably a result of conversions during the Roman empire. Concerning the similarity between Sephardi and Ashkenazi, he argues that the reasons are uncertain, but that it is likely to be caused by Sephardic Jews having "Mediterranean" ancestry also, like the Ashkenazi. Concerning mitochondrial DNA, and particularly Y DNA, he accepts that there are superficial signs of a Middle Eastern origins, but he argues that this can be ignored as it is may came from a small number of ancestors.[17]

An autosomal DNA study carried out in 2010 by Atzmon et al. examined the origin of Iranian, Iraqi, Syrian, Turkish, Greek, Sephardic, and Ashkenazi Jewish communities. The study compared these Jewish groups with 1043 unrelated individuals from 52 world-wide populations. To further examine the relationship between Jewish communities and European populations, 2407 European subjects were assigned and divided into 10 groups based on geographic region of their origin. This study confirmed previous findings of shared Middle Eastern origin of the above Jewish groups and found that "the genetic connections between the Jewish populations became evident from the frequent IBD across these Jewish groups (63% of all shared segments). Jewish populations shared more and longer segments with one another than with non-Jewish populations, highlighting the commonality of Jewish origin. Among pairs of populations ordered by total sharing, 12 out of the top 20 were pairs of Jewish populations, and "none of the top 30 paired a Jewish population with a non-Jewish one". Atzmon concludes that "Each Jewish group demonstrated Middle Eastern ancestry and variable admixture from host population, while the split between Middle Eastern and European/Syrian Jews, calculated by simulation and comparison of length distributions of IBD segments, occurred 100–150 generations ago, which was described as "compatible with a historical divide that is reported to have occurred more than 2500 years ago" as the Jewish community in Iraq and Iran were formed by Jews in the Babylonian and Persian empires during and after Babylonian exile. The main difference between Mizrahi and Ashkenazi/Sephardic Jews was the absence of Southern European components in the former. According to these results, European/Syrian Jewish populations, including the Ashkenazi Jewish community, were formed latter, as a result of the expulsion of Jews from Palestine, during Roman rule. Concerning Ashkenazi Jews, this study found that genetic dates "are incompatible with theories that Ashkenazi Jews are for the most part the direct lineal descendants of converted Khazars or Slavs". Citing Behar, Atzmon states that "Evidence for founder females of Middle Eastern origin has been observed in all Jewish populations based on non overlapping mitochondrial haplotypes with coalescence times >2000 years". The closest people related to Jewish groups were the Palestinians, Bedouins, Druze, Greeks, and Italians. Regarding this relationship, the authors conclude that "These observations are supported by the significant overlap of Y chromosomal haplogroups between Israeli and Palestinian Arabs with Ashkenazi and non-Ashkenazi Jewish populations".[11][12][14][75][76]

In 2011, Moorjani et al.[77] detected 3%–5% sub-Saharan African ancestry in all eight of the diverse Jewish populations (Ashkenazim, Syrian Jews, Iranian Jews, Iraqi Jews, Greek Jews, Turkey Jews, Italian Jews) that they analyzed. The timing of this African admixture among all Jewish populations was identical although the exact date was not determined (1600–3400 years ago) Although African admixture was determined among South Europeans and Near Eastern population too, this admixture was found to be younger compared to the Jewish populations. This findings the authors explained as evidence regarding common origin of this 8 main Jewish groups. "It is intriguing that the Mizrahi Irani and Iraqi Jews—who are thought to descend at least in part from Jews who were exiled to Babylon about 2,600 years ago share the signal of African admixture. A parsimonious explanation for these observations is that they reflect a history in which many of the Jewish groups descend from a common ancestral population which was itself admixed with Africans, prior to the beginning of the Jewish diaspora that occurred in 8th to 6th century BC" the authors concludes.[12][78]

In 2012, a genetic study carried out under the leadership of Harry Ostrer, from Albert Einstein College of Medicine, which was published in the Proceedings of the National Academy of Sciences found that North African Jews are genetically closer to European and Middle Eastern Jews than to their long term host population.[79] The study showed that the
"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." [80]

A 2012 study by Eran Elhaik[81] analyzed data collected for previous studies and concluded that the DNA of Eastern and Central European Jewish populations indicates that their ancestry is "a mosaic of Caucasus, European, and Semitic ancestries". For the study, Palestinians were assumed to be a valid genetic surrogate of ancient Jews, whereas the Druze were assumed to be non-Semitic immigrants into the Levant. Armenians and Georgians were also used as surrogate populations for the Khazars, who spoke a Turkic language unrelated to Georgian or Armenian. On this basis, a relatively strong connection to the Caucasus was proposed because of the stronger genetic similarity of these Jewish groups to modern Armenians, Georgians, Azerbaijani Jews, Druze and Cypriots, compared to a weaker genetic similarity with Palestinians. This proposed Caucasian component of ancestry was in turn taken to be consistent with the Khazarian Hypothesis as an explanation of part of the ancestry of Ashkenazi Jews.

A study by Haber et al. (2013) noted that while previous studies of the Levant, which had focused mainly on diaspora Jewish populations, showed that the "Jews form a distinctive cluster in the Middle East", these studies did not make clear "whether the factors driving this structure would also involve other groups in the Levant". The authors found strong evidence that modern Levant populations descend from two major apparent ancestral populations. One set of genetic characteristics which is shared with modern-day Europeans and Central Asians is most prominent in the Levant amongst "Lebanese, Armenians, Cypriots, Druze and Jews, as well as Turks, Iranians and Caucasian populations". The second set of inherited genetic characteristics is shared with populations in other parts of the Middle East as well as some African populations. Levant populations in this category today include "Palestinians, Jordanians, Syrians, as well as North Africans, Ethiopians, Saudis, and Bedouins". Concerning this second component of ancestry, the authors remark that while it correlates with "the pattern of the Islamic expansion", and that "a pre-Islamic expansion Levant was more genetically similar to Europeans than to Middle Easterners," they also say that "its presence in Lebanese Christians, Sephardi and Ashkenazi Jews, Cypriots and Armenians might suggest that its spread to the Levant could also represent an earlier event". The authors also found a strong correlation between religion and apparent ancestry in the Levant:
"all Jews (Sephardi and Ashkenazi) cluster in one branch; Druze from Mount Lebanon and Druze from Mount Carmel are depicted on a private branch; and Lebanese Christians form a private branch with the Christian populations of Armenia and Cyprus placing the Lebanese Muslims as an outer group. The predominantly Muslim populations of Syrians, Palestinians and Jordanians cluster on branches with other Muslim populations as distant as Morocco and Yemen."[82]
In September 2013 at the American Society of Human Genetics meeting, geneticists including M. Metspalu, D. M. Behar, Y. Baran Rosset N. Kopelman, B. Yunusbayev, A. Gladstein, M. F. Hammer, S. Tzur, E. Halperin, K. Skorecki and R. Villems presented a new genetic study specifically aimed to explore genetic relationship between Ashkenazi Jews and Khazars. The study assembled the largest sample set available to date for assessment of Ashkenazi Jewish genetic origins, containing genome-wide single-nucleotide polymorphism data in 1,774 samples from 107 Jewish and non-Jewish populations and 15 populations from the region historically associated with the Khazar kingdom at its peak. The presentation titled "No indication of Khazar genetic ancestry among Ashkenazi Jews" found that
Ashkenazi Jewish samples share the greatest genetic ancestry with other Jewish populations, and among non-Jewish populations, with groups from Mediterranean Europe and the Middle East, and that they have no particular signal of genetic sharing with populations from the Caucasus. Thus, analysis of the most comprehensive set of Jewish and other Middle Eastern and European populations together with a large sample from the region of the Khazar kingdom does not support the hypothesis of a significant contribution of the elusive Khazars into the gene pool of the Ashkenazi Jews."[83]

Comparison with the genetic heritage of non-Jewish populations

The Samaritans

The Samaritans are an ancient northern population of historic Israel, where they are historically well identified since at least the 4th century BC. They define themselves as the descendants of tribes of Ephraim and Manasseh (two tribes from the Tribe of Joseph) living in the Kingdom of Israel before its destruction in 722 BC. For them, the Jews are the descendants of the Israelites from ancient southern kingdom of Judah (and Jerusalem).

A 2004 study by Shen et al. compared the Y-DNA and DNA-mt Samaritans of 12 men with those of 158 men who were not Samaritans, divided between 6 Jewish populations (Ashkenazi origin, Moroccan, Libyan, Ethiopian, Iraqi and Yemeni) and 2 non-Jewish populations from Israel (Druze and Arab). The study concludes that significant similarities exist between paternal lines of Jews and Samaritans, but the maternal lines differ between the two populations. The pair-wise genetic distances (Fst) between 11 populations from AMOVA applied to the Y-chromosomal and mitochondrial data. For the Y-chromosome, all Jewish groups, except for the Ethiopians, are closely related to each other. They do not differ significantly from Samaritans (0.041) and Druze (0.033), but are different from Palestinians (0.163), Africans (0.219), and Europeans (0.111). Nevertheless, the data in this study indicated that the Samaritan and Jewish Y-chromosomes have a greater affinity than do those of the Samaritans and their geographical neighbors, the Palestinians.[38]

The Lembas

The Lemba clans are scattered among the Bantu-speaking tribes in Zimbabwe and northern South Africa. The oral tradition traces the origin of the Jewish Lembas to Saana in Yemen. Some practices seem reminiscent of Jewish practices (circumcision, food law,…). Two studies have attempted to determine the paternal origin of these tribes. The first by A. Spurdle and T. Jenkins[84] dates from 1996 and suggests that more than half of Lembas tested are of Semitic origin.[Note 11] The second study by Mark G. Thomas et al.[85] dates from 2000 and also suggests that part of Lembas have a Semitic origin that can come from a mixture of Arabs and Jews.[Note 12] In addition, the authors show that clans Lemba (Buba clan) has a large proportion of the former CMH.

Inhabitants of the Iberian Peninsula

According to a 2008 study by Adams[86] the inhabitants of the Iberian Peninsula have an average of 20% of Sephardi Jewish ancestry with significant geographical variations ranging from 0% on Minorca to 36.3% in southern Portugal (the term Sephardi is used here in its strict sense to mean the Jews settled in the Iberian peninsula before the expulsions in and after 1492). Part of this admixture might also, according to the authors, be of Neolithic origin.

See also

Notes and references

Notes

References

Further reading

  • Abu El-Haj, Nadia. The Genealogical Science: The Search for Jewish Origins and the Politics of Epistemology, University of Chicago Press, 2012
  • Falk, Raphael. 'Zionut Vehabiologia Shel Hayehudim (Zionism and the Biology of the Jews), Tel Aviv: Resling, 2006 (not yet available in English)
  • Ostrer, Harry. Legacy: A Genetic History of the Jewish People, Oxford University Press, 2012

External links

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