paragraph_text: Witherspoon et al. (2007) have argued that even when individuals can be reliably assigned to specific population groups, it may still be possible for two randomly chosen individuals from different populations/clusters to be more similar to each other than to a randomly chosen member of their own cluster. They found that many thousands of genetic markers had to be used in order for the answer to the question "How often is a pair of individuals from one population genetically more dissimilar than two individuals chosen from two different populations?" to be "never". This assumed three population groups separated by large geographic ranges (European, African and East Asian). The entire world population is much more complex and studying an increasing number of groups would require an increasing number of markers for the same answer. The authors conclude that "caution should be used when using geographic or genetic ancestry to make inferences about individual phenotypes." Witherspoon, et al. concluded that, "The fact that, given enough genetic data, individuals can be correctly assigned to their populations of origin is compatible with the observation that most human genetic variation is found within populations, not between them. It is also compatible with our ﬁnding that, even when the most distinct populations are considered and hundreds of loci are used, individuals are frequently more similar to members of other populations than to members of their own population."

paragraph_text: A 2001 study by Nebel et al. showed that both Ashkenazi and Sephardic Jewish populations share the same overall paternal Near Eastern 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 authors also report on Eu 19 (R1a) chromosomes, which are very frequent in Central and Eastern Europeans (54%–60%) at elevated frequency (12.7%) in Ashkenazi Jews. They hypothesized that the differences among Ashkenazim Jews could reflect low-level gene flow from surrounding European populations and/or genetic drift during isolation. A later 2005 study by Nebel et al., found a similar level of 11.5% of male Ashkenazim belonging to R1a1a (M17+), the dominant Y-chromosome haplogroup in Central and Eastern Europeans.

paragraph_text: It is estimated that in the 11th century Ashkenazi Jews composed only three percent of the world's Jewish population, while at their peak in 1931 they accounted for 92 percent of the world's Jews. Immediately prior to the Holocaust, the number of Jews in the world stood at approximately 16.7 million. Statistical figures vary for the contemporary demography of Ashkenazi Jews, oscillating between 10 million and 11.2 million. Sergio DellaPergola in a rough calculation of Sephardic and Mizrahi Jews, implies that Ashkenazi make up less than 74% of Jews worldwide. Other estimates place Ashkenazi Jews as making up about 75% of Jews worldwide.

paragraph_text: Late Carboniferous and Early Permian insect orders include both extant groups, their stem groups, and a number of Paleozoic groups, now extinct. During this era, some giant dragonfly-like forms reached wingspans of 55 to 70 cm (22 to 28 in), making them far larger than any living insect. This gigantism may have been due to higher atmospheric oxygen levels that allowed increased respiratory efficiency relative to today. The lack of flying vertebrates could have been another factor. Most extinct orders of insects developed during the Permian period that began around 270 million years ago. Many of the early groups became extinct during the Permian-Triassic extinction event, the largest mass extinction in the history of the Earth, around 252 million years ago.

paragraph_text: A study of haplotypes of the Y-chromosome, published in 2000, addressed the paternal origins of Ashkenazi Jews. Hammer et al. found that the Y-chromosome of Ashkenazi and Sephardic 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%." 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 percent of DNA from the Ashkenazi Y chromosome, which is used to trace the male lineage, originated in the Near East," Richards said.

paragraph_text: Ashkenazi Jews represent the bulk of modern Jewry, with at least 70% of Jews worldwide (and up to 90% prior to World War II and the Holocaust). As a result of their emigration from Europe, Ashkenazim also represent the overwhelming majority of Jews in the New World continents, in countries such as the United States, Canada, Argentina, Australia, and Brazil. In France, the immigration of Jews from Algeria (Sephardim) has led them to outnumber the Ashkenazim. Only in Israel is the Jewish population representative of all groups, a melting pot independent of each group's proportion within the overall world Jewish population.

paragraph_text: 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". 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 closely related, the source of non-Jewish admixture is mainly southern European, while Mizrahi Jews show evidence of admixture with other Middle Eastern populations and Sub-Saharan Africans. Behar et al. have remarked on an especially close relationship of Ashkenazi Jews and modern Italians.

paragraph_text: According to a report published in 2014, about 43% of all Jews reside in Israel (6.1 million), and 40% in the United States (5.7 million), with most of the remainder living in Europe (1.4 million) and Canada (0.4 million). These numbers include all those who self-identified as Jews in a socio-demographic study or were identified as such by a respondent in the same household. The exact world Jewish population, however, is difficult to measure. In addition to issues with census methodology, disputes among proponents of halakhic, secular, political, and ancestral identification factors regarding who is a Jew may affect the figure considerably depending on the source.

paragraph_text: A 2006 study found Ashkenazi Jews to be a clear, homogeneous genetic subgroup. Strikingly, regardless of the place of origin, Ashkenazi Jews can be grouped in the same genetic cohort – that is, regardless of whether an Ashkenazi Jew's ancestors came from Poland, Russia, Hungary, Lithuania, or any other place with a historical Jewish population, they belong to the same ethnic group. The research demonstrates the endogamy of the Jewish population in Europe and lends further credence to the idea of Ashkenazi Jews as an ethnic group. Moreover, though intermarriage among Jews of Ashkenazi descent has become increasingly common, many Haredi Jews, particularly members of Hasidic or Hareidi sects, continue to marry exclusively fellow Ashkenazi Jews. This trend keeps Ashkenazi genes prevalent and also helps researchers further study the genes of Ashkenazi Jews with relative ease. It is noteworthy that these Haredi Jews often have extremely large families.

paragraph_text: The population geneticist Sewall Wright developed one way of measuring genetic differences between populations known as the Fixation index, which is often abbreviated to FST. This statistic is often used in taxonomy to compare differences between any two given populations by measuring the genetic differences among and between populations for individual genes, or for many genes simultaneously. It is often stated that the fixation index for humans is about 0.15. This translates to an estimated 85% of the variation measured in the overall human population is found within individuals of the same population, and about 15% of the variation occurs between populations. These estimates imply that any two individuals from different populations are almost as likely to be more similar to each other than either is to a member of their own group. Richard Lewontin, who affirmed these ratios, thus concluded neither "race" nor "subspecies" were appropriate or useful ways to describe human populations. However, others have noticed that group variation was relatively similar to the variation observed in other mammalian species.

paragraph_text: The development of type 2 diabetes is caused by a combination of lifestyle and genetic factors. While some of these factors are under personal control, such as diet and obesity, other factors are not, such as increasing age, female gender, and genetics. Obesity is more common in women than men in many parts of Africa. A lack of sleep has been linked to type 2 diabetes. This is believed to act through its effect on metabolism. The nutritional status of a mother during fetal development may also play a role, with one proposed mechanism being that of DNA methylation. The intestinal bacteria Prevotella copri and Bacteroides vulgatus have been connected with type 2 diabetes.

paragraph_text: Abu el-Haj argues that genomics and the mapping of lineages and clusters liberates "the new racial science from the older one by disentangling ancestry from culture and capacity."[citation needed] As an example, she refers to recent work by Hammer et al., which aimed to test the claim that present-day Jews are more closely related to one another than to neighbouring non-Jewish populations. Hammer et al. found that the degree of genetic similarity among Jews shifted depending on the locus investigated, and suggested that this was the result of natural selection acting on particular loci. They focused on the non-recombining Y-chromosome to "circumvent some of the complications associated with selection".

paragraph_text: Genetic studies on Jews show that most Jews worldwide bear a common genetic heritage which originates in the Middle East, and that they bear their strongest resemblance to the peoples of the Fertile Crescent. The genetic composition of different Jewish groups shows that Jews share a common genetic pool dating back 4,000 years, as a marker of their common ancestral origin. Despite their long-term separation and beside their shared genetic origin, Jews also maintained a common culture, tradition, and language.

paragraph_text: A number of studies have reported associations between pathogen load in an area and human behavior. Higher pathogen load is associated with decreased size of ethnic and religious groups in an area. This may be due high pathogen load favoring avoidance of other groups, which may reduce pathogen transmission, or a high pathogen load preventing the creation of large settlements and armies that enforce a common culture. Higher pathogen load is also associated with more restricted sexual behavior, which may reduce pathogen transmission. It also associated with higher preferences for health and attractiveness in mates. Higher fertility rates and shorter or less parental care per child is another association that may be a compensation for the higher mortality rate. There is also an association with polygyny which may be due to higher pathogen load, making selecting males with a high genetic resistance increasingly important. Higher pathogen load is also associated with more collectivism and less individualism, which may limit contacts with outside groups and infections. There are alternative explanations for at least some of the associations although some of these explanations may in turn ultimately be due to pathogen load. Thus, polygny may also be due to a lower male:female ratio in these areas but this may ultimately be due to male infants having increased mortality from infectious diseases. Another example is that poor socioeconomic factors may ultimately in part be due to high pathogen load preventing economic development.

paragraph_text: This can give rise to the situation in which two dialects (defined according to this paradigm) with a somewhat distant genetic relationship are mutually more readily comprehensible than more closely related dialects. In one opinion, this pattern is clearly present among the modern Romance languages, with Italian and Spanish having a high degree of mutual comprehensibility, which neither language shares with French, despite some claiming that both languages are genetically closer to French than to each other:[citation needed] In fact, French-Italian and French-Spanish relative mutual incomprehensibility is due to French having undergone more rapid and more pervasive phonological change than have Spanish and Italian, not to real or imagined distance in genetic relationship. In fact, Italian and French share many more root words in common that do not even appear in Spanish.

paragraph_text: A 2010 study on Jewish ancestry by Atzmon-Ostrer et al. stated "Two major groups were identified by principal component, phylogenetic, and identity by descent (IBD) analysis: Middle Eastern Jews and European/Syrian Jews. 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 both groups – the Middle Eastern Jews and European/Syrian Jews – shared common ancestors in the Middle East about 2500 years ago. The study examines genetic markers spread across the entire genome and shows that the Jewish groups (Ashkenazi and non Ashkenazi) share large swaths of DNA, indicating close relationships and that each of the Jewish groups in the study (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. 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 the genetic-similarity between Ashkenazi Jews and Italians may be due to inter-marriage and conversions in the time of the Roman Empire. It was also found that any two Ashkenazi Jewish participants in the study shared about as much DNA as fourth or fifth cousins.

paragraph_text: The genome-wide genetic study carried out in 2010 by Behar et al. examined the genetic relationships among all major Jewish groups, including Ashkenazim, as well as the genetic relationship between these Jewish groups and non-Jewish ethnic populations. The study found that contemporary Jews (excluding Indian and Ethiopian Jews) have a close genetic relationship with 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".

paragraph_text: By the 2000 census, demographic changes including the end to slavery, immigration from Europe and Asia, assimilation of multiracial persons, and other factors resulted in a population in which 6.2% of the population identified as black, 40% as pardo, and 55% as white. Essentially most of the black population was absorbed into the multi-racial category by intermixing. A 2007 genetic study found that at least 29% of the middle-class, white Brazilian population had some recent (since 1822 and the end of the colonial period) African ancestry.

paragraph_text: A limited partnership (LP) is a form of partnership similar to a general partnership except that while a general partnership must have at least two general partners (GPs), a limited partnership must have at least one GP and at least one limited partner.

paragraph_text: Other historians believe that conversion during the Roman era was limited in number and did not account for much of the Jewish population growth, due to various factors such as the illegality of male conversion to Judaism in the Roman world from the mid-2nd century. Another factor that would have made conversion difficult in the Roman world was the halakhic requirement of circumcision, a requirement that proselytizing Christianity quickly dropped. The Fiscus Judaicus, a tax imposed on Jews in 70 CE and relaxed to exclude Christians in 96 CE, also limited Judaism's appeal. In addition, historians argue the very figure (4 million) that had been guessed to account for the population of Jews in the ancient Roman Empire is an error that has long been disproven and thus the assumption that conversion impacted Jewish population growth in ancient Rome on a large scale is false. The 8 million figure is also in doubt as it may refer to a census of total Roman citizens.

Question: The group representing at least 70% of Jews worldwide and Italians may be genetically similar due to what two factors?
Answer: inter-marriage and conversions in the time of the Roman Empire