Editing Ashkenazi Jews (section)

===Genetic origins===
Efforts to identify the origins of Ashkenazi Jews through DNA analysis began in the 1990s. There are three types of genetic origin testing, autosomal DNA (atDNA), [[mitochondrial DNA]] (mtDNA), and Y-chromosomal DNA ([[Y-DNA]]). Autosomal DNA is a mixture from an individual's entire ancestry. Y-DNA shows a male's lineage along his paternal line. mtDNA shows any person's lineage only along their maternal line. [[Genome-wide association study|Genome-wide association studies]] have also been used for genetic origin testing.

Like most DNA studies of human migration patterns, the earliest studies on Ashkenazi Jews focused on the Y-DNA and mtDNA segments of the human genome. Both segments are unaffected by [[recombination (biology)|recombination]] (except for the ends of the Y chromosome – the [[pseudoautosomal region]]s known as PAR1 and PAR2), thus allowing tracing of direct maternal and paternal lineages.

These studies revealed that Ashkenazi Jews originate from an ancient (2000–700 BCE) population of the Middle East who spread to Europe.<ref name="tony-frudakis-book">{{cite book |title=Molecular Photofitting: Predicting Ancestry and Phenotype Using DNA |author=Tony Nick Frudakis |page=383 |url=https://books.google.com/books?id=9vXeydpj7VkC&q=ashkenazi+jews+middle+eastern+origin+bronze+age&pg=PA383 |isbn=978-0-08-055137-1 |date=19 July 2010 |publisher=Elsevier |access-date=10 October 2020 |archive-date=26 January 2022 |archive-url=https://web.archive.org/web/20220126174841/https://books.google.com/books?id=9vXeydpj7VkC&q=ashkenazi+jews+middle+eastern+origin+bronze+age&pg=PA383 |url-status=live }}</ref> Ashkenazic Jews display the homogeneity of a [[Population bottleneck|genetic bottleneck]], meaning they descend from a larger population whose numbers were greatly reduced but recovered through a few founding individuals. Although the Jewish people, in general, were present across a wide geographical area as described, genetic research by Gil Atzmon of the Longevity Genes Project at [[Albert Einstein College of Medicine]] suggests "that Ashkenazim branched off from other Jews around the time of the destruction of the First Temple, 2,500 years ago ... flourished during the Roman Empire but then went through a 'severe bottleneck' as they dispersed, reducing a population of several million to just 400 families who left Northern Italy around the year 1000 for Central and eventually Eastern Europe."<ref>{{cite news |title=What Do a Bunch of Old Jews Know About Living Forever? |author=Jesse Green |work=New York Magazine |date=6 November 2011 |url=https://nymag.com/news/features/ashkenazi-jews-2011-11/ |access-date=19 July 2013 |archive-date=2 June 2022 |archive-url=https://web.archive.org/web/20220602051356/https://nymag.com/news/features/ashkenazi-jews-2011-11/ |url-status=live }}</ref>

Various studies have drawn diverging conclusions about the degree and sources of the non-Levantine [[Miscegenation|admixture]] in Ashkenazim,<ref name="Summary of Recent Genetic Studies"/> particularly the extent of the non-Levantine origin in maternal lineages, which is in contrast to the predominant Levantine genetic origin in paternal lineages. But all studies agree that both lineages have genetic overlap with the [[Fertile Crescent]], albeit at differing rates. Collectively, Ashkenazi Jews are less genetically diverse than other [[Jewish ethnic divisions]], due to their genetic bottleneck.<ref>{{cite news|last=Bloch|first=Talia|title=The Other Jewish Genetic Diseases|url=http://forward.com/articles/112426/the-other-jewish-genetic-diseases/|access-date=8 November 2013|newspaper=[[The Jewish Daily Forward]]|date=19 August 2009|archive-date=3 November 2013|archive-url=https://web.archive.org/web/20131103194252/http://forward.com/articles/112426/the-other-jewish-genetic-diseases/|url-status=live}}</ref>

====Male lineages: Y-chromosomal DNA====
Most genetic studies of Ashkenazi Jews conclude that the male lines were from the Middle East.<ref name=WhoAreTheJews>{{cite journal |url=http://ftp.beitberl.ac.il/~bbsite/misc/ezer_anglit/klali/05_123.pdf |title=Who are the Jews? |author=Jared Diamond |year=1993 |access-date=8 November 2010 |url-status=dead |archive-url=https://web.archive.org/web/20110721133548/http://ftp.beitberl.ac.il/~bbsite/misc/ezer_anglit/klali/05_123.pdf |archive-date=21 July 2011 |journal=Natural History |volume=102 |issue=11 |pages=12–19}}</ref><ref name="pnas.org">{{cite journal |author1=M.F. Hammer |author2=A.J. Redd |author3=E.T. Wood |author4=M.R. Bonner |author5=H. Jarjanazi |author6=T. Karafet |author7=S. Santachiara-Benerecetti |author8=A. Oppenheim |author9=M.A. Jobling |author10=T. Jenkins‡‡ |author11=H. Ostrer |author12=B. Bonné-Tamir |name-list-style=amp |title=Jewish and Middle Eastern non-Jewish populations share a common pool of Y-chromosome biallelic haplotypes |journal=PNAS |volume=97 |number=12 |pages=6769–6774 |doi= 10.1073/pnas.100115997 |pmid=10801975 |pmc=18733 |bibcode = 2000PNAS...97.6769H |year=2000 |doi-access=free }}</ref><ref name="nytimes-chromosome-study">{{cite news|title=Y Chromosome Bears Witness to Story of the Jewish Diaspora|first=Nicholas|last=Wade|url=https://www.nytimes.com/2000/05/09/science/y-chromosome-bears-witness-to-story-of-the-jewish-diaspora.html|newspaper=[[The New York Times]]|date=9 May 2000|access-date=10 October 2012|archive-date=24 November 2017|archive-url=https://web.archive.org/web/20171124113719/http://www.nytimes.com/2000/05/09/science/y-chromosome-bears-witness-to-story-of-the-jewish-diaspora.html|url-status=live}}</ref>

A 2000 study by Hammer ''et al.''<ref name="hammer">{{cite journal|title=Jewish and Middle Eastern non-Jewish populations share a common pool of Y-chromosome biallelic haplotypes|first=M. F.|last=Hammer|author2=A. J. Redd|author3=E. T. Wood|author4=M. R. Bonner|author5=H. Jarjanazi|author6=T. Karafet|author7=S. Santachiara-Benerecetti|author8=A. Oppenheim|author9=M. A. Jobling|author10=T. Jenkins|author11=H. Ostrer|author12=B. Bonné-Tamir|journal=Proceedings of the National Academy of Sciences|date=9 May 2000|doi=10.1073/pnas.100115997|volume=97|pmid=10801975|issue=12|pmc=18733|bibcode=2000PNAS...97.6769H|pages=6769–74|url=https://lra.le.ac.uk/bitstream/2381/362/1/6769.pdf|doi-access=free|access-date=4 November 2018|archive-date=9 August 2017|archive-url=https://web.archive.org/web/20170809151930/https://lra.le.ac.uk/bitstream/2381/362/1/6769.pdf|url-status=live}}</ref> found that the [[Y chromosome|Y-chromosome]] of Ashkenazi and [[Sephardic Jews]] contained mutations that are also common among Middle Eastern peoples, but uncommon among indigenous Europeans. This suggests that Ashkenazim male ancestors are mostly from the Middle East. Ashkenazim had less than 0.5% male [[genetic admixture]] per generation over an estimated 80 generations, with "relatively minor contribution of European Y chromosomes to the Ashkenazim," and the total admixture estimate "very similar to Motulsky's average estimate of 12.5%". This supported the finding that "Diaspora Jews from Europe, Northwest Africa, and the [[Near East]] resemble each other more closely than they resemble their non-Jewish neighbors." "Past research found that 50%–80% of DNA from the Ashkenazi Y chromosome, which is used to trace the male lineage, originated in the Near East," Richards said. The population has subsequently spread out.

A 2001 study by Nebel ''et al.'' showed that Ashkenazi and Sephardic Jews share overall Near Eastern paternal ancestries. 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. The study also found Eu 19 ([[R1a]]) chromosomes had elevated frequency among Ashkenazi Jews (13%), and they are very frequent in Central and Eastern Europeans (54–60%). They hypothesized that the differences among Ashkenazim could reflect low-level [[gene flow]] from surrounding European populations or [[genetic drift]] during isolation.<ref>{{Cite journal |pmc = 1274378|year = 2001|last1 = Nebel|first1 = A.|title = The y Chromosome Pool of Jews as Part of the Genetic Landscape of the Middle East|journal = American Journal of Human Genetics|volume = 69|issue = 5|pages = 1095–1112|last2 = Filon|first2 = D.|last3 = Brinkmann|first3 = B.|last4 = Majumder|first4 = P. P.|last5 = Faerman|first5 = M.|last6 = Oppenheim|first6 = A.|pmid = 11573163|doi = 10.1086/324070}}</ref> A 2005 study by Nebel ''et al.'', found a similar level of 11.5% of male Ashkenazim belonging to [[R1a|R1a1a (M17+)]], the dominant Y-chromosome haplogroup in Central and Eastern Europeans.<ref>{{cite journal |vauthors=Nebel A, Filon D, Faerman M, Soodyall H, Oppenheim A |title=Y chromosome evidence for a founder effect in Ashkenazi Jews |journal=Eur. J. Hum. Genet. |volume=13 |issue=3 |pages=388–91 |date=March 2005 |pmid=15523495 |doi=10.1038/sj.ejhg.5201319 |doi-access=free }}</ref> However, a 2017 study, of Ashkenazi [[Levites]] where the proportion reaches 50%, found a "rich variation of haplogroup R1a outside of Europe which is phylogenetically separate from the typically European R1a branches", and concludes that the particular R1a-Y2619 sub-clade is evidence for a local origin, and that this validates the "Middle Eastern origin of the Ashkenazi Levite lineage" which had previously been concluded based on a few samples.<ref>{{Cite journal |doi=10.1038/s41598-017-14761-7|pmid=29097670|pmc=5668307|bibcode=2017NatSR...714969B|title=The genetic variation in the R1a clade among the Ashkenazi Levites' y chromosome|journal=Scientific Reports|volume=7|issue=1|page=14969|last1=Behar|first1=Doron M.|last2=Saag|first2=Lauri|last3=Karmin|first3=Monika|last4=Gover|first4=Meir G.|last5=Wexler|first5=Jeffrey D.|last6=Sanchez|first6=Luisa Fernanda|last7=Greenspan|first7=Elliott|last8=Kushniarevich|first8=Alena|last9=Davydenko|first9=Oleg|last10=Sahakyan|first10=Hovhannes|last11=Yepiskoposyan|first11=Levon|last12=Boattini|first12=Alessio|last13=Sarno|first13=Stefania|last14=Pagani|first14=Luca|last15=Carmi|first15=Shai|last16=Tzur|first16=Shay|last17=Metspalu|first17=Ene|last18=Bormans|first18=Concetta|last19=Skorecki|first19=Karl|last20=Metspalu|first20=Mait|last21=Rootsi|first21=Siiri|last22=Villems|first22=Richard|year=2017}}</ref>

====Female lineages: Mitochondrial DNA====

A 2006 study by Behar ''et al.'',<ref name="behar"/> of 1,000 units of [[Haplogroup K (mtDNA)|haplogroup K]] (mtDNA), suggested that about 40% of today's Ashkenazim descend from just four women who were "likely from a [[Hebrews|Hebrew]]/[[Levant]]ine mtDNA pool" originating in the Middle East in the 1st and 2nd centuries CE. The rest of Ashkenazi mtDNA reportedly originated from about 150 women, most of whom were also likely of Middle Eastern origin.<ref name="behar"/> Specifically, although haplogroup K is common throughout western Eurasia, its global distribution makes it very unlikely that "the four aforementioned founder lineages entered the Ashkenazi mtDNA pool via gene flow from a European host population".

A 2013 study of Ashkenazi mitochondrial DNA by a team led by Martin B. Richards tested all 16,600 DNA units of mtDNA, and found that the four main female Ashkenazi founders had descent lines that were established in Europe 10,000 to 20,000 years in the past<ref name=NYTimesEuropeanWomen>{{cite news |url=https://www.nytimes.com/2013/10/09/science/ashkenazi-origins-may-be-with-european-women-study-finds.html |newspaper=[[The New York Times]] |title=Genes Suggest European Women at Root of Ashkenazi Family Tree |author=Nicholas Wade |date=8 October 2013 |access-date=18 February 2017 |archive-date=23 April 2019 |archive-url=https://web.archive.org/web/20190423212620/https://www.nytimes.com/2013/10/09/science/ashkenazi-origins-may-be-with-european-women-study-finds.html |url-status=live }}</ref> while most of the remaining minor founders also have a deep European ancestry. The study argued that the great majority of Ashkenazi maternal lineages were not brought from the Near East or the Caucasus, but instead assimilated within Europe, primarily of Italian and Old French origins.<ref name="jewishvoiceny-ashkenazi">{{cite news |author=Martin Gershowitz |url=http://jewishvoiceny.com/index.php?option=com_content&id=5546:new-study-finds-most-ashkenazi-jews-genetically-linked-to-europe&Itemid=325 |title=New Study Finds Most Ashkenazi Jews Genetically Linked to Europe |newspaper=[[Jewish Voice]] |date=16 October 2013 |access-date=31 October 2013 |archive-date=26 August 2012 |archive-url=https://web.archive.org/web/20120826120627/http://jewishvoiceny.com/index.php?option=com_content |url-status=live }}</ref> The study estimated that more than 80% of Ashkenazi maternal ancestry comes from women indigenous to (mainly prehistoric Western) Europe, and only 8% from the Near East, while the origin of the remainder is undetermined.<ref name=Costa>{{cite journal | author = M. D. Costa and 16 others | title = A substantial prehistoric European ancestry amongst Ashkenazi maternal lineages | journal = Nature Communications | year = 2013 | doi = 10.1038/ncomms3543 | volume = 4 | issue = 1 | page = 2543 | pmid=24104924 | pmc=3806353|bibcode = 2013NatCo...4.2543C }}</ref><ref name=NYTimesEuropeanWomen /> According to the study this "point to a significant role for the conversion of women in the formation of Ashkenazi communities."<ref name=Costa/><ref name="forward.com">{{cite news |url=http://forward.com/articles/185399/jewish-womens-genes-traced-mostly-to-europe-not/ |work=The Jewish Daily Forward |title=Jewish Women's Genes Traced Mostly to Europe – Not Israel – Study Hits Claim Ashkenazi Jews Migrated From Holy Land |date=12 October 2013 |access-date=25 November 2013 |archive-date=24 December 2018 |archive-url=https://web.archive.org/web/20181224213559/https://forward.com/news/breaking-news/185399/jewish-womens-genes-traced-mostly-to-europe-not/ |url-status=live }}</ref><ref name="haaretz.com">{{cite news |url=http://www.haaretz.com/jewish-world/jewish-world-news/.premium-1.551825 |newspaper=[[Haaretz]] |title=Study traces Ashkenazi roots to European women who probably converted to Judaism – The genetic analysis traced the lineage of many Ashkenazi Jews to four maternal founders in Europe |author=Ofer Aderet |date=11 October 2013 |access-date=16 November 2014 |archive-date=17 July 2014 |archive-url=https://web.archive.org/web/20140717045459/http://www.haaretz.com/jewish-world/jewish-world-news/.premium-1.551825 |url-status=live }}</ref><ref name="bbc.co.uk">{{cite news |url=https://www.bbc.co.uk/news/science-environment-24442352 |work=BBC News |title=European link to Jewish maternal ancestry |author=Melissa Hogenboom |date=9 October 2013 |access-date=2 July 2018 |archive-date=13 February 2020 |archive-url=https://web.archive.org/web/20200213033342/https://www.bbc.co.uk/news/science-environment-24442352 |url-status=live }}</ref><ref name="news.sciencemag.org">{{cite news |url=https://www.science.org/content/article/did-modern-jews-originate-italy |work=Science Magazine |title=Did Modern Jews Originate in Italy? |author=Michael Balter |date=8 October 2013 |access-date=30 June 2022 |archive-date=23 June 2022 |archive-url=https://web.archive.org/web/20220623074322/https://www.science.org/content/article/did-modern-jews-originate-italy |url-status=live }}</ref> [[Karl Skorecki]] criticized the study, arguing that while it "re-opened the question of the maternal origins of Ashkenazi Jewry, the phylogenetic analysis in the manuscript does not 'settle' the question."<ref>{{cite news|url=https://www.bbc.co.uk/news/science-environment-24442352|title=European link to Jewish ancestry|first=Melissa|last=Hogenboom|date=9 October 2013|work=BBC News|access-date=2 July 2018|archive-date=13 February 2020|archive-url=https://web.archive.org/web/20200213033342/https://www.bbc.co.uk/news/science-environment-24442352|url-status=live}}</ref>

A 2014 study by Fernández ''et al.'' found that Ashkenazi Jews display a frequency of haplogroup K in their maternal DNA, suggesting an ancient Near Eastern matrilineal origin, similar to the results of the Behar study in 2006. Fernández noted that this observation clearly contradicts the results of the 2013 study led by Richards that suggested a European source for 3 exclusively Ashkenazi K lineages.<ref name="ReferenceD"/>

====Association and linkage studies (autosomal DNA)====
In [[genetic epidemiology]], a [[genome-wide association study]] (GWA study, or GWAS) is an examination of all or most of the genes (the genome) of different individuals of a particular species to  see how much the genes vary from individual to individual. These  techniques were originally designed for epidemiological uses, to identify genetic associations with observable traits.<ref name="Pearson">{{cite journal |doi=10.1001/jama.299.11.1335| volume=299| issue=11| pages=1335–44 |author=Pearson TA, Manolio TA |title=How to interpret a genome-wide association study| journal=JAMA|year=2008 |pmid=18349094 | last2=Manolio}}</ref>

A 2006 study by Seldin ''et al.'' used over 5,000 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%, while most southern Europeans (Italians, Greeks, Portuguese, Spaniards) showed >85%. Both Ashkenazi and 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".<ref name="pmid17044734">{{Cite journal|display-authors=etal|vauthors=Seldin MF, Shigeta R, Villoslada P|date=September 2006|title=European population substructure: clustering of northern and southern populations|journal=PLOS Genet.|volume=2|issue=9|pages=e143|doi=10.1371/journal.pgen.0020143|pmc=1564423|pmid=17044734 |doi-access=free }}</ref>

A 2007 study by Bauchet ''et al.'' found that Ashkenazim were most closely clustered with Arabic North African populations than with the global population, and in the European structure analysis, they share similarities only with Greeks and Southern Italians, reflecting their east Mediterranean origins.<ref>{{cite journal |last1=Rosenberg |first1=Noah A. |year=2002 |title=Genetic structure of human populations |journal=[[Science (journal)|Science]] |volume=298 |issue=5602 |pages=2381–85 |doi=10.1126/science.1078311 |pmid=12493913 |bibcode=2002Sci...298.2381R |first2=Jonathan K |last2=Pritchard |first3=JL |last3=Weber |last4=Cann |first4=HM |last5=Kidd |first5=KK |last6=Zhivotovsky |first6=LA |last7=Feldman |first7=MW|s2cid=8127224 |display-authors=etal}}</ref><ref>{{cite journal |last1=Bauchet |first1=Marc |year=2007 |title=Measuring European Population Stratification with Microarray Genotype Data |journal=American Journal of Human Genetics |volume=80 |issue=5 |pages=948–56 |doi=10.1086/513477 |pmid=17436249 |pmc=1852743 |first2=Brian |last2=McEvoy |last3=Pearson |first3=Laurel N. |last4=Quillen |first4=Ellen E. |last5=Sarkisian |first5=Tamara |last6=Hovhannesyan |first6=Kristine |last7=Deka |first7=Ranjan |last8=Bradley |first8=Daniel G. |last9=Shriver |first9=Mark D. |display-authors=etal}}</ref>

A 2010 study of Jewish ancestry by Atzmon-Ostrer ''et al.'' identified two major groups: Middle Eastern Jews and European/Syrian Jews, by using "principal component, phylogenetic, and identity by descent (IBD) analysis". "The IBD segment sharing and the proximity of European Jews to each other and to southern European populations suggested similar origins for European Jewry and refuted large-scale genetic contributions of Central and Eastern European and Slavic populations to the formation of Ashkenazi Jewry", as the two groups share ancestors in the Middle East about 2500 years ago. The study examines genetic markers spread across the entire genome and finds that the Jewish groups (Ashkenazi and non-Ashkenazi) share large swaths of DNA, indicating close relationships, and that each studied Jewish group (Iranian, Iraqi, Syrian, Italian, Turkish, Greek and Ashkenazi) has its own genetic signature but is more closely related to the other Jewish groups than to their fellow non-Jewish countrymen.<ref>{{cite news |url=http://www.sciencenews.org/view/generic/id/59938/title/Tracing_Jewish_roots |title=Tracing Jewish roots |first=Tina Hesman |last=Saey |work=ScienceNews |date=3 June 2010 |access-date=25 January 2011 |archive-date=1 May 2011 |archive-url=https://web.archive.org/web/20110501112339/http://www.sciencenews.org/view/generic/id/59938/title/Tracing_Jewish_roots |url-status=live }}</ref> Atzmon's team found that the SNP markers in genetic segments of 3 million DNA letters or longer were 10 times more likely to be identical among Jews than non-Jews. Results of the analysis also tally with biblical accounts of the fate of the Jews. The study also found that with respect to non-Jewish European groups, the population most closely related to Ashkenazi Jews are modern-day Italians. The study speculated that this similarity may be due to inter-marriage and conversions during the Roman Empire. It was also found that any two Ashkenazi Jewish participants shared about as much DNA as fourth or fifth cousins.<ref name="Atzmon2010">{{cite journal |first1=Gil |last1=Atzmon |first2=Li |last2=Hao |first3=Itsik |last3=Pe'Er |first4=Christopher |last4=Velez |first5=Alexander |last5=Pearlman |first6=Pier Francesco |last6=Palamara|first7=Bernice |last7=Morrow |first8=Eitan |last8=Friedman |first9=Carole |last9=Oddoux |first10=Edward |last10=Burns |first11=Harry |last11 =Ostrer |name-list-style=amp |title=Abraham's Children in the Genome Era: Major Jewish Diaspora Populations Comprise Distinct Genetic Clusters with Shared Middle Eastern Ancestry |journal=[[American Journal of Human Genetics]] |volume=86 |issue=6 |pages=850–59 |year=2010 |doi=10.1016/j.ajhg.2010.04.015 |pmid=20560205 |pmc=3032072}}</ref><ref>{{cite news|title=Genes Set Jews Apart, Study Finds|url=http://www.americanscientist.org/science/pub/-674|access-date=8 November 2013|newspaper=[[American Scientist]]|archive-date=9 November 2013|archive-url=https://web.archive.org/web/20131109005918/http://www.americanscientist.org/science/pub/-674|url-status=live}}</ref>

A 2010 study by Bray ''et al.'', using [[SNP array|SNP]] [[DNA microarray|microarray]] techniques and [[linkage analysis]], found that when assuming [[Druze]] and [[Palestinian Arabs|Palestinian Arab]] populations to represent the reference to world Jewry ancestor genome, 35% to 55% of the modern Ashkenazi genome may be of European origin, and that European "admixture is considerably higher than previous estimates by studies that used the Y chromosome" with this reference point.<ref>{{cite news |last1=Kaplan |first1=Karen |title=DNA ties Ashkenazi Jews to group of just 330 people from Middle Ages |url=https://www.latimes.com/science/sciencenow/la-sci-sn-ashkenazi-jews-dna-diseases-20140909-story.html |work=Los Angeles Times |date=9 September 2014 |access-date=21 February 2020 |archive-date=21 February 2020 |archive-url=https://web.archive.org/web/20200221193214/https://www.latimes.com/science/sciencenow/la-sci-sn-ashkenazi-jews-dna-diseases-20140909-story.html |url-status=live }}</ref> The authors interpreted this linkage disequilibrium in the Ashkenazi Jewish population as matching signs "of interbreeding or 'admixture' between Middle Eastern and European populations".<ref>{{cite journal |title=Signatures of founder effects, admixture, and selection in the Ashkenazi Jewish population |first1=Steven M. |last1=Bray |first2=Jennifer G. |last2=Mulle |first3=Anne F. |last3=Dodd |first4=Ann E. |last4=Pulver |first5=Stephen |last5=Wooding |first6=Stephen T. |last6=Warren |journal=[[Proceedings of the National Academy of Sciences|PNAS]] |volume=107|issue=37 |pages=16222–27 |doi=10.1073/pnas.1004381107 |year=2010 |pmid=20798349|bibcode=2010PNAS..10716222B |pmc=2941333|doi-access=free }}</ref> On the Bray ''et al.'' tree, Ashkenazi Jews were found to be a genetically more divergent population than [[Russians]], [[Orcadians]], French, [[Basques]], [[Sardinians]], Italians and [[Tuscany|Tuscans]]. The study also observed that Ashkenazim are more diverse than their Middle Eastern relatives, which was counterintuitive because Ashkenazim are supposed to be a subset, not a superset, of their assumed geographical source population. Bray ''et al.'' therefore suggest that these results reflect a history of mixing between genetically distinct populations in Europe. However, it is possible that Ashkenazim's high heterozygocity was due to a relaxation of marriage prescription in their ancestors, while the low heterozygocity in te Middle East is due to maintenance of [[Cousin marriage in the Middle East|FBD marriage]] there. Therefore, Ashkenazim distinctiveness as found in the Bray ''et al.'' study may come from their ethnic endogamy (ethnic inbreeding), which allowed them to "mine" their ancestral gene pool in the context of relative reproductive isolation from European neighbors, and not from clan endogamy (clan inbreeding). Consequently, their higher diversity compared to Middle Easterners stems from the latter's marriage practices, not necessarily from the former's admixture with Europeans.<ref>{{cite web |url=http://anthropogenesis.kinshipstudies.org/2012/07/how-to-interpret-patterns-of-genetic-variation-admixture-divergence-inbreeding/ |title=How to Interpret Patterns of Genetic Variation? Admixture, Divergence, Inbreeding, Cousin Marriage |publisher=Anthropogenesis |date=24 July 2012 |access-date=19 July 2013 |archive-date=10 March 2013 |archive-url=https://web.archive.org/web/20130310161611/http://anthropogenesis.kinshipstudies.org/2012/07/how-to-interpret-patterns-of-genetic-variation-admixture-divergence-inbreeding/ |url-status=live }}</ref> 

A 2010 genome-wide genetic study by Behar ''et al.'' examined the genetic relationships among all major Jewish groups, including Ashkenazim, and their genetic relationship with non-Jewish ethnic populations. It found that today's Jews (except Indian and Ethiopian Jews) are closely related to people from the [[Levant]]. The authors explained that "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".<ref>{{cite journal |url=http://bhusers.upf.edu/dcomas/wp-content/uploads/2011/02/Behar2010.pdf |title=The genome-wide structure of the Jewish people |journal=[[Nature (journal)|Nature]] |volume=466 |issue=7303 |date=8 July 2010 |pages=238–42 |first1=Doron M. |last1=Behar |first2=Bayazit |last2=Yunusbayev |first3=Mait |last3=Metspalu |first4=Ene |last4=Metspalu |first5=Saharon |last5=Rosset |first6=Jüri |last6=Parik |first7=Siiri |last7=Rootsi |first8=Gyaneshwer |last8=Chaubey |first9=Ildus |last9=Kutuev |first10=Guennady |last10=Yudkovsky |first11=Elza K. |last11=Khusnutdinova |first12=Oleg |last12=Balanovsky |first13=Ornella |last13=Semino |first14=Luisa |last14=Pereira |first15=David |last15=Comas |first16=David |last16=Gurwitz |first17=Batsheva |last17=Bonne-Tamir |first18=Tudor |last18=Parfitt |first19=Michael F. |last19=Hammer |first20=Karl |last20=Skorecki |first21=Richard |last21=Villems |doi=10.1038/nature09103 |access-date=4 September 2013 |pmid=20531471 |bibcode=2010Natur.466..238B |s2cid=4307824 |archive-date=23 May 2013 |archive-url=https://web.archive.org/web/20130523105113/http://bhusers.upf.edu/dcomas/wp-content/uploads/2011/02/Behar2010.pdf |url-status=live }}</ref>

A 2013 study by Behar ''et al.'' found evidence among Ashkenazim of mixed European and Levantine origins. The authors found Ashkenazi had the greatest affinity and shared ancestry firstly with other Jewish groups from southern Europe, Syria, and North Africa, and secondly with both southern Europeans (such as Italians) and modern Levantines (such as the [[Druze]], Cypriots, Lebanese and [[Samaritans]]). The study found no affinity of Ashkenazim to northern Caucasus populations, and no more affinity to modern south Caucasus and eastern Anatolian populations (such as [[Armenians]], [[Azerbaijanis]], [[Georgians]], and Turks) than found in other Jews or non-Jewish Middle Easterners (such as the [[Kurds]], Iranians, Druze and Lebanese).<ref name = "WayneState2013">{{cite journal |last1 = Behar |first1 = Doron M. |last2 = Metspalu |first2 = Mait |last3 = Baran |first3 = Yael |last4 = Kopelman |first4 = Naama M. |last5 = Yunusbayev |first5 = Bayazit |last6 = Gladstein |first6 = Ariella |last7 = Tzur |first7 = Shay |last8 = Sahakyan |first8 = Havhannes |last9 = Bahmanimehr |first9 = Ardeshir |last10 = Yepiskoposyan |first10 = Levon |last11 = Tambets |first11 = Kristiina |last12 = Khusnutdinova |first12 = Elza K. |last13 = Kusniarevich |first13 = Aljona |last14 = Balanovsky |first14 = Oleg |first15 = Elena |last15 = Balanovsky |first16 = Lejla |last16 = Kovacevic |first17 = Damir |last17 = Marjanovic |first18 = Evelin |last18 = Mihailov |first19 = Anastasia |last19 = Kouvatsi |first20 = Costas |last20 = Traintaphyllidis |first21 = Roy J. |last21 = King |first22 = Ornella |last22 = Semino |first23 = Antonio |last23 = Torroni |first24 = Michael F. |last24 = Hammer |first25 = Ene |last25 = Metspalu |first26 = Karl |last26 = Skorecki |first27 = Saharon |last27 = Rosset |first28 = Eran |last28 = Halperin |first29 = Richard |last29 = Villems |first30 = Noah A. |last30 = Rosenberg |year = 2013 |title = No Evidence from Genome-Wide Data of a Khazar Origin for the Ashkenazi Jews |url = http://digitalcommons.wayne.edu/humbiol_preprints/41/ |journal = Human Biology Open Access Pre-Prints |volume = 85 |publisher = [[Wayne State University]] |issue = 41 |access-date = 14 October 2014 |archive-date = 12 January 2020 |archive-url = https://web.archive.org/web/20200112192035/https://digitalcommons.wayne.edu/humbiol_preprints/41/ |url-status = live }} Final version at http://digitalcommons.wayne.edu/humbiol/vol85/iss6/9/ {{Webarchive|url=https://web.archive.org/web/20141014231218/http://digitalcommons.wayne.edu/humbiol/vol85/iss6/9/ |date=14 October 2014 }}</ref>

A 2017 autosomal study by Xue, Shai Carmi ''et al.'' found an admixture of Middle-Eastern and European ancestry in Ashkenazi Jews: with the European component comprising ≈50%–70% (estimated at "possibly 60%") and largely being of a southern European source and a minority eastern European, and the remainder (estimated at possibly ≈40%) being Middle Eastern ancestry showing the strongest affinity to Levantine populations such as the Druze and Lebanese.<ref name="ReferenceC"/>

A 2018 study, referencing the popular theory of Ashkenazi Jewish (AJ) origins in "an initial settlement in Western Europe (Northern France and Germany), followed by migration to Poland and an expansion there and in the rest of Eastern Europe", tested "whether Ashkenazi Jews with recent origins in Eastern Europe are genetically distinct from Western European Ashkenazi". The study concluded that "Western AJ consist of two slightly distinct groups: one that descends from a subset of the original founders [who remained in Western Europe], and another that migrated there back from Eastern Europe, possibly after absorbing a limited degree of gene flow".<ref>{{Cite journal|last1=Granot-Hershkovitz|first1=Einat|last2=Karasik|first2=David|last3=Friedlander|first3=Yechiel|last4=Rodriguez-Murillo|first4=Laura|last5=Dorajoo|first5=Rajkumar|last6=Liu|first6=Jianjun|last7=Sewda|first7=Anshuman|last8=Peter|first8=Inga|last9=Carmi|first9=Shai|last10=Hochner|first10=Hagit|date=December 2018|title=A study of Kibbutzim in Israel reveals risk factors for cardiometabolic traits and subtle population structure|journal=European Journal of Human Genetics|language=en|volume=26|issue=12|pages=1848–1858|doi=10.1038/s41431-018-0230-3|pmid=30108283 |pmc=6244281 |issn=1476-5438}}</ref>

A 2022 study of genome data from the medieval Jewish cemetery of [[Erfurt]] found at least two related but genetically distinct Jewish groups: one closely related to Middle Eastern populations and especially similar to modern Ashkenazi Jews from France and Germany and modern Sephardic Jews from Turkey; the other group had a substantial contribution from Eastern European populations. But today Ashkenazi Jews from eastern Europe no longer exhibit this genetic variability, and instead, their genomes resemble a nearly even mixture of the two Erfurt groups (with about 60% from the first group and 40% from the second).<ref name=":2"/>