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. 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 refuted the Khazar theory of Ashkenazi ancestry. 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's 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" Concerning North African Jews, autosomal genetic analysis in 2012 revealed that North African Jews are genetically close to European Jews. This finding "shows that North African Jews date to biblical-era Israel, and are not largely the descendants of natives who converted to Judaism,"
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. 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.
A study conducted in 2013 found no evidence of a Khazar origin for Ashkenazi Jews and suggested that "Ashkenazi Jews share the greatest genetic ancestry with other Jewish populations, and among non-Jewish populations, with groups from Europe and the Middle East. No particular similarity of Ashkenazi Jews with populations from the Caucasus is evident, particularly with the populations that most closely represent the Khazar region. In this view, analysis of Ashkenazi Jews together with a large sample from the region of the Khazar Khaganate would corroborate earlier results that Ashkenazi Jews derive their ancestry primarily from populations of the Middle East and Europe, that they possess considerable shared ancestry with other Jewish populations, and that there is no indication of a significant genetic contribution either from within or from north of the Caucasus region."
In 2016, together with R. Das, P. Wexler and M. Pirooznia, Elhaik advanced the view that the first Ashkenazi populations to speak the Yiddish language came from areas near four villages in Eastern Turkey along the Silk Road whose names derived from the word "Ashkenaz", arguing that Iranian, Greek, Turkish, and Slav populations converted on that travel route before moving to Khazaria, where a small-scale conversion took place. The study was dismissed by Sergio DellaPergola as a "falsification", noting it failed to include Jewish groups such as the Italkim and Sephardic Jews, to whom Ashkenazi Jews are closely related genetically. Shaul Stampfer, a professor of Soviet and East European Jewry at the Hebrew University, called Elhaik's research "basically nonsense". Elhaik replied that the DNA of non-Ashkenazic Jews would not affect the origin of DNA hypothesized for the former. Prof. Dovid Katz, founder of Vilnius University’s Yiddish Institute criticized the study’s linguistic analysis. “The authors have melded accurate but contextually meaningless genetic correlations with laughable linguistic theories that now proliferate, sadly, as a consequence of a much weakened Yiddish academic environment internationally ... there is not a single word or sound in Yiddish that comes from Iranian or Turkish". In joint study published in 2016 by Genome Biology and Evolution, Pavel Flegontov from Department of Biology and Ecology, Faculty of Science, University of Ostrava, Czech Republic, A.A. Kharkevich Institute of Linguistics, Russian Academy of Sciences, Moscow, Mark G. Thomas from Research Department of Genetics, Evolution and Environment, University College London, UK, Valentina Fedchenko from Saint Petersburg State University, and George Starostin from Russian State University for the Humanities, dismissed both the genetic and linguistic components of Elhaik et al. study arguing that "GPS is a provenancing tool suited to inferring the geographic region where a modern and recently unadmixed genome is most likely to arise, but is hardly suitable for admixed populations and for tracing ancestry up to 1000 years before present, as its authors have previously claimed. Moreover, all methods of historical linguistics concur that Yiddish is a Germanic language, with no reliable evidence for Slavic, Iranian, or Turkic substrata." The authors concluded:
"In our view, Das and co-authors have attempted to fit together a marginal and unsupported interpretation of the linguistic data with a genetic provenancing approach, GPS, that is at best only suited to inferring the most likely geographic location of modern and relatively unadmixed genomes, and tells nothing of population history and origin."
The authors, in a non peer-reviewed response, defended the methodological adequacy of their approach. In 2016 Elhaik having reviewed the literature searching for a ‘Jüdische Typus’ argued that there is no genomic hallmark for Jewishness. While he allows that in the future it is possible that a ‘Jewish’ marker may turn up, so far, in his view, Jewishness turns out to be socially defined (a socionome), determined by non-genetic factors. On 31 October 2016 a corrigendum to the initial GPS paper by Elhaik et al. 2014 was published in Nature Communications. The corrigendum included a conflict of interests statement in which one of the authors (Tatiana Tatarinova) acknowledged a relationship with Prosapia Genetics. The GPS tool, remained freely available on the lab website of Dr. Tatiana Tatarinova, but as of December 2016 the link is broken. In 2017, the same authors further supported a non-Levantine origin of Ashkenazi Jews claiming that "Overall, the combined results (of linguistics study and GPS tool) are in a strong agreement with the predictions of the Irano-Turko-Slavic hypothesis and rule out an ancient Levantine origin for AJs, which is predominant among modern-day Levantine populations (e.g., Bedouins and Palestinians)." Elhaik's and Das' work was among others, strongly criticized by Marion Aptroot from University of Düsseldorf, who in the study published by Genome Biology and Evolution claimed that "Das et al. create a narrative based on genetic, philological and historical research and state that the findings of the three disciplines support each other...Incomplete and unreliable data from times when people were not counted regardless of sex, age, religion or financial or social status on the one hand, and the dearth of linguistic evidence predating the 15th century on the other, leave much room for conjecture and speculation. Linguistic evidence, however, does not support the theory that Yiddish is a Slavic language, and textual sources belie the thesis that the name Ashkenaz was brought to Eastern Europe directly from a region in the Near East. Although the focus and methods of research may be different in the humanities and the sciences, scholars should try to account for all evidence and observations, regardless of the field of research. Seen from the standpoint of the humanities, certain aspects of the article by Das et al. fall short of established standards".