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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== Jews have a complex history of migrations. Since the 1970s, many studies have attempted to determine whether 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.). Contradictory answers were given according to the loci used.〔 One explanation for these contradictions is that the variations associated with a locus are influenced by natural selection.〔 Since the late 1980s and especially since the beginning of the twenty-first century, geneticists have worked on analysis of the Y chromosome (transmitted from father to son), or 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. 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.〔(), JPost〕 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.〔〔Molecular Photofitting: Predicting Ancestry and Phenotype Using DNA by Tony Nick Frudakis P:383 ()〕 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. Thus, analysis of Ashkenazi Jews together with a large sample from the region of the Khazar Khaganate corroborates the 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." The maternal lineages of Jewish populations, studied by looking at mitochondrial DNA, are generally more heterogeneous.〔 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.〔Richard Lewontin, "Is There a Jewish Gene?", ''New York Review of Books'', 6 December 2012〕 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".〔 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. 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",〔(NICHOLAS WADE, "Genes Suggest European Women at Root of Ashkenazi Family Tree" ), ''New York Times'', 8 October 2013, accessed 15 October 2013〕 suggesting that Jewish males migrated to Europe and took new wives from the local population, and converted them to Judaism. However, another study by Eva Fernandez et. al. published in 2014 which studied the DNA of the Neolithic period and its modern descendants suggested that Ashkenazi Jews maternally originated in the Ancient Near East, contrary to the suggestion of Richards at al (2013).〔(Ancient DNA Analysis of 8000 B.C. Near Eastern Farmers Supports an Early Neolithic Pioneer Maritime Colonization of Mainland Europe through Cyprus and the Aegean Islands )〕 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. 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".〔http://bhusers.upf.edu/dcomas/wp-content/uploads/2011/02/Behar2010.pdf〕 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. 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.〔〔(【引用サイトリンク】title=Jews Are a 'Race,' Genes Reveal – )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Genetic studies of Jewish origins」の詳細全文を読む スポンサード リンク
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