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: Modern tufa is formed from alkaline waters, supersaturated with calcite. On emergence, waters degas CO due to the lower atmospheric pCO (see partial pressure), resulting in an increase in pH. Since carbonate solubility decreases with increased pH, precipitation is induced. Supersaturation may be enhanced by factors leading to a reduction in pCO, for example increased air - water interactions at waterfalls may be important, as may photosynthesis.

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: 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.

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: The Bellarosa Connection is a 1989 novella by the American author Saul Bellow. The book takes the form of an ongoing dialogue between the Fonstein family about the impact of the Holocaust. This is an especially significant story as it represents, along with "Mr. Sammler's Planet", Bellow's most significant commentary on the Holocaust. In the book, the Bellarosa Connection signifies Billy Rose's Madison Square Garden benefit for the Jews of Europe on the most immediate level, but, more deeply, becomes a point of departure for Bellow to consider the American Jewish response to European Jews' experience during World War II. As Bellow's protagonist comes to grips with the past, his experience distances American Jewry's position from that of its European counterparts. The book moves then to Israel in order to present the three major homelands of the World's Jewry.

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: In contrast to the general American Jewish community, which is dwindling due to low fertility and high intermarriage and assimilation rates, the Orthodox Jewish community of the United States is growing rapidly. Among Orthodox Jews, the fertility rate stands at about 4.1 children per family, as compared to 1.9 children per family among non-Orthodox Jews, and intermarriage among Orthodox Jews is practically non-existent, standing at about 2%, in contrast to a 71% intermarriage rate among non-Orthodox Jews. In addition, Orthodox Judaism has a growing retention rate; while about half of those raised in Orthodox homes previously abandoned Orthodox Judaism, that number is declining. According to The New York Times, the high growth rate of Orthodox Jews will eventually render them the dominant demographic force in New York Jewry.

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: On the other hand, Orthodox Jews subscribing to Modern Orthodoxy in its American and UK incarnations, tend to be far more right-wing than both non-orthodox and other orthodox Jews. While the overwhelming majority of non-Orthodox American Jews are on average strongly liberal and supporters of the Democratic Party, the Modern Orthodox subgroup of Orthodox Judaism tends to be far more conservative, with roughly half describing themselves as political conservatives, and are mostly Republican Party supporters. Modern Orthodox Jews, compared to both the non-Orthodox American Jewry and the Haredi and Hasidic Jewry, also tend to have a stronger connection to Israel due to their attachment to Zionism.

paragraph_text: A 2010 study by Bray et al., using SNP microarray techniques and linkage analysis found that when assuming Druze and Palestinian Arab populations to represent the reference to world Jewry ancestor genome, between 35 to 55 percent of the modern Ashkenazi genome can possibly 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. Assuming this reference point the linkage disequilibrium in the Ashkenazi Jewish population was interpreted as "matches signs of interbreeding or 'admixture' between Middle Eastern and European populations". On the Bray et al. tree, Ashkenazi Jews were found to be a genetically more divergent population than Russians, Orcadians, French, Basques, Italians, Sardinians and 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 postulate that these results reflect not the population antiquity but a history of mixing between genetically distinct populations in Europe. However, it's possible that the relaxation of marriage prescription in the ancestors of Ashkenazim that drove their heterozygosity up, while the maintenance of the FBD rule in native Middle Easterners have been keeping their heterozygosity values in check. Ashkenazim distinctiveness as found in the Bray et al. study, therefore, 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.

paragraph_text: Classification seeks to describe the diversity of bacterial species by naming and grouping organisms based on similarities. Bacteria can be classified on the basis of cell structure, cellular metabolism or on differences in cell components, such as DNA, fatty acids, pigments, antigens and quinones. While these schemes allowed the identification and classification of bacterial strains, it was unclear whether these differences represented variation between distinct species or between strains of the same species. This uncertainty was due to the lack of distinctive structures in most bacteria, as well as lateral gene transfer between unrelated species. Due to lateral gene transfer, some closely related bacteria can have very different morphologies and metabolisms. To overcome this uncertainty, modern bacterial classification emphasizes molecular systematics, using genetic techniques such as guanine cytosine ratio determination, genome-genome hybridization, as well as sequencing genes that have not undergone extensive lateral gene transfer, such as the rRNA gene. Classification of bacteria is determined by publication in the International Journal of Systematic Bacteriology, and Bergey's Manual of Systematic Bacteriology. The International Committee on Systematic Bacteriology (ICSB) maintains international rules for the naming of bacteria and taxonomic categories and for the ranking of them in the International Code of Nomenclature of Bacteria.

paragraph_text: In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits (called a byte). Each byte is able to represent 256 different numbers (28 = 256); either from 0 to 255 or −128 to +127. To store larger numbers, several consecutive bytes may be used (typically, two, four or eight). When negative numbers are required, they are usually stored in two's complement notation. Other arrangements are possible, but are usually not seen outside of specialized applications or historical contexts. A computer can store any kind of information in memory if it can be represented numerically. Modern computers have billions or even trillions of bytes of memory.

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 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: 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: 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: Some scholars believe that Modern Orthodoxy arose from the religious and social realities of Western European Jewry. While most Jews consider Modern Orthodoxy traditional today, some (the hareidi and hasidic groups) within the Orthodox community consider some elements to be of questionable validity. The neo-Orthodox movement holds that Hirsch's views are not accurately followed by Modern Orthodoxy. [See Torah im Derech Eretz and Torah Umadda "Relationship with Torah im Derech Eretz" for a more extensive listing.]

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.

Question: Italians and the group of Jews representing the bulk of modern Jewry may be genetically similar due to what two factors?
Answer: inter-marriage and conversions in the time of the Roman Empire