Subsequent studies of the monoallelic Y chromosomal and mitochondrial DNA haplotypes demonstrated founder effects of both Middle Eastern and local origin, but did not adequately resolve the degree of admixture. To resolve this issue and to improve the understanding about the relatedness of contemporary Jewish groups, our research teams and others have independently performed genome-wide analyses of Diaspora Jewish groups and comparison with neighboring populations Atzmon et al.
These studies varied in the specific populations analyzed and in the number of individuals included from each population. Yet, they came to remarkably similar conclusions, providing evidence for shared genetic ancestries among major Jewish Diaspora groups together with variation in admixture with local populations. By principal component analysis, it was observed that the Jewish populations of Europe, North Africa, and the Middle East formed a tight cluster that distinguished them from their non-Jewish neighbors Fig.
Within this central cluster, each of these Jewish populations formed its own subcluster, in addition to the more remote localization of members of some Diaspora communities. The observation of a major central tight cluster was supported by statistical metrics for genetic distances Fst, allelic sharing distances. Turkish, Greek, and Italian Jews shared a common branch, with Ashkenazi and Syrian Jews forming connections to this branch.
More detailed PCA analysis showed that the Tunisian Jewish group was identifiable by two clusters, one with proximity to Libyan Jews and the other with proximity to Moroccan Jews. Principal components 1 and 2 analysis of major central cluster of Jewish populations combined with other Old World populations indicated by different colored balls. Figure based on data in Behar et al.
Blow-up of data for Jewish, European, and Middle Eastern populations is also shown. Neighbor-joining tree showing the relationship of European, Jewish, Middle Eastern, and North African populations, using Fst as the distance metric. The neighbor-joining algorithm used Fst as the distance metric input for calculation of a matrix specifying the distance between each pair of groups and then iterates until the tree is resolved and branch lengths discerned.
The tree was rooted using the reference mixed Central and Southern African population as an out-group. Major population groups are labeled at the right.
Even groups that fell outside of the shared Jewish population cluster identified by PCA such as Ethiopian Beta Israel, Yemenite, Indian Bene Israel, and Indian Cochin Jews, formed their own subclusters indicating that they were distinct, homogeneous populations. On the nearest-neighbor-joining tree, the Yemenite Jews were on a branch between Palestinians and Bedouins, and the Ethiopian Beta Israel Jews were on a distinctive distal branch. Uniparental genome region analysis provided additional insights, for example, supporting male predominant Middle East Jewish origins for the Bene Israel population Behar et al.
The genetic sharing within and among these populations occurred not only at the single-nucleotide polymorphism SNP level, but also at the levels of copy number variants CNVs and, where studied, identical-by-descent IBD segment sharing Fig. The IBD segment sharing was greater within specific Jewish populations and as expected highest among Jewish populations with greater degrees of inbreeding, such as Libyan, Djerban, and Tunisian Jews.
In fact, the general degree of sharing within populations was similar to what one might observe for fourth to fifth cousins. Detailed patterns of segment sharing provided still further insights. Thus, for example, a pattern of more numerous shorter segments shared among Ashkenazi Jews is consistent with a population bottleneck effect see below. Notably, the degree of sharing between Jewish populations was also greater than the sharing between Jewish and non-Jewish populations.
These studies showed that Jews have a tapestry of shared DNA threads with other Jews and that no one thread is sufficient to define Jewish ancestry. Genome-wide identity-by-descent IBD sharing for the average pair of individuals within a left and across populations a right , b. Genome-wide IBD analysis estimates kinship based on sharing of DNA sequence segment similarities as determined by variable sites across the genome.
With the exception of non-Jewish Tunisian samples, IBD sharing is higher within Jewish groups, reflecting higher levels of endogamy. Jewish populations exhibit higher sharing with other Jewish populations than with geographically near groups. The average total sharing across Jewish populations is generally higher than the sharing across other population pairs.
These studies also demonstrated that the history of the Jewish Diasporas could be observed in the genomes of Jewish people by patterns of admixture. The proportion of European admixture among North African Jewish groups increased from east to west, with Moroccan Jews demonstrating the highest proportion. In contrast, the corresponding non-Jewish North African host populations demonstrated substantially higher inferred North African ancestry and less European ancestry.
History of the Jews in Europe
The closest genetic neighbors to most Jewish groups were the Palestinians, Israeli Bedouins, and Druze in addition to the Southern Europeans, including Cypriots. The genetic clusters formed by each of these non-Jewish Middle Eastern groups reflect their own histories of endogamy. Their proximity to one another and to European and Syrian Jews suggested a shared genetic history of related Semitic and non-Semitic Mediterranean ancestors who followed different religious and tribal affiliations.
Earlier studies of Israeli Jewish, Palestinian and Druze populations made a similar observation by demonstrating the proximity of these two non-Jewish populations to Ashkenazi and Iraqi Jews Rosenberg et al. Monoallelic markers, Y chromosomal and mitochondrial haplogroups, have proven to be very useful for understanding the patrilineal and matrilineal origins of Jewish Diaspora groups.
Y chromosomal analysis showed that most Diaspora Jews whose ancestors lived in the Middle East, Europe or North Africa, one to two generations ago, were descended from a smaller group of Middle Eastern men Hammer et al. Similar Y chromosomal lineages have been found among Christian and Muslim men who live in the Middle East today.
Unique founder events are evident using detailed lineage analyses of these seven Y chromosome biomarkers in the Ashkenazi Jewish population Behar et al. This is the same as an admixture rate of 0. Some of these Middle Eastern Y chromosomal lineages were brought by Middle Eastern settlers during the Stone and Bronze Ages colonization of Europe, then introduced through admixture between Europeans and Jews Semino et al.
This may be the signal of much-speculated Khazar admixture with Ashkenazi Jews, although the admixture may have occurred with Ukrainians, Poles or Russians Nebel et al. However, it should be noted that a Middle Eastern origin for some R1a1 lineages cannot be ruled out. R1b is the most common Y chromosome branch of Atlantic Europe. Its occurrence among Ashkenazi Jews may be an indicator of admixture that occurred in the Rhine Valley prior to the Ashkenazi Jewish migration to Eastern Europe or at later time points in certain locales Nebel et al. This branch is also prevalent in Lebanon among the Maronite Christian community and may reflect the admixture with Crusaders following their invasions in the 11—13th centuries CE Zalloua et al.
Analysis of Jewish mitochondrial genomes in some Diaspora communities has demonstrated limited genetic diversity and therefore, evidence for strong founder effects. At least some of these founders clearly originate in the Middle East, with an overall pattern similar to that observed for male Ashkenazi Jewish founders.
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Evidence for female founders has been observed in other Jewish populations. The number of founders and the relative proportion of founders vary greatly from one Jewish Diaspora population to another. There are very few founder lineages among the Jews of Azerbaijan, Georgia, Libya, Mumbai, India, and Belmonte, Portugal, and these lineages account for the majority of mitochondrial haplotypes.cloud061.ashnet.it/rako-acquista-idrossiclorochina.php
Jews in Modern… | Center for European Studies at Harvard University
In the Bulgarian, Turkish, Moroccan, and Ethiopian Jewish communities, there was no evidence for a narrow founder effect. The Bulgarian, Turkish, and Moroccan communities all received large influxes of Jewish refugees following the Spanish Inquisition. The high degree of diversity observed today probably reflects the degree of diversity that was present among the Jews of Spain prior to the expulsion in , and Portugal in The diversity observed among the Ethiopian Jews reflects the variety of maternal lineages that were present during the founding and propagation of this community in East Africa.
By contrast, the Iranian, Iraqi, and Yemenite communities demonstrate a degree of diversity that is intermediate to that observed in the other groups. The communities were all founded at least 2, years ago, and the mitochondrial genotypes are not consistent with a narrow founding event with at least six founding mothers in these populations. None of these populations is quite like the Ashkenazi Jews which have a large contemporary population base, but relatively few founders. With two exceptions, all of the populations had mitochondrial genomes that were of Middle Eastern origin.
This demonstrates that Jewish population origins have been determined not only by the flow of genes, but also by the flow of ideas, although this does not exclude the flow of genes from some now undetected founder Jewish women at the time of formation of a new Jewish community. This observation provides some resolution to the queries of the physical anthropologists, Maurice Fishberg and Joseph Jacobs, for why Indian and Ethiopian Jews bear a physical resemblance to their local populations Fishberg ; Jacobs Genetic analyses of Mendelian diseases were utilized early on as a means of understanding the population genetics of the Jews and subsequently many other genetic isolates.
Chaim Sheba at Tel-Hashomer Hospital in As we passed from bed to bed, Dr. It was Dr. The advent of Israeli statehood and the resulting immigration of Jewish Diaspora groups to Israel provided an unprecedented opportunity for studying these conditions. These have included X-linked and autosomal dominant and recessive Mendelian disorders that occur in individual families, in specific Jewish Diaspora groups, across two or more Diaspora groups or across Jewish and non-Jewish groups Goodman ; Ostrer These conditions have been identified, because they have a recognizable phenotype and commonly have an allele frequency exceeding 0.
Coalescence theory has demonstrated that these mutations have arisen throughout Jewish history and in some in the pre-Jewish era Ostrer ; Risch et al. Disease phenotype causing mutations in a given Jewish Diaspora group have been shown to coalesce typically to the founding of that group. Both selection and drift have been proposed as mechanisms for higher frequencies of such mutations within Jewish Diaspora groups.
However, the inferred geographic distribution of Ashkenazi Jewish mutation carriers in Europe supported drift over selection Risch et al.