Genetic studies on Turkish people
Population genetics research has been conducted on the ancestry of the modern Turkish people (not to be confused with Turkic peoples) in Turkey. Such studies are relevant for the demographic history of the population as well as health reasons, such as population specific diseases. Some studies have sought to determine the relative contributions of the Turkic peoples of Central Asia, from where the Seljuk Turks began migrating to Anatolia after the Battle of Manzikert in 1071, which led to the establishment of the Anatolian Seljuk Sultanate in the late 11th century, and prior populations in  the area who were culturally assimilated during the Seljuk and the Ottoman periods. Turkish genomic variation, along with several other Western Asian populations, looks most similar to genomic variation of South European populations such as southern Italians. Western Asian genomes, including Turkish ones, have been greatly influenced by early agricultural populations in the area; later population movements, such as those of Turkic speakers, also contributed. Multiple studies have found similarities or common ancestry between Turkish people and present-day or historic populations in the Mediterranean, West Asia and the Caucasus. Other studies have found that Turkish people cluster with Southern  and Mediterranean European populations along with groups in the northern part of Southwest Asia (such as the populations from Caucasus, Iraq, and Iran) and have the lowest fixation index distance from Caucasus and Iranian-Syrian populations. Multiple studies have also found Central Asian contributions. Central Asian connection. Several studies have investigated to what extent a gene flow from Central Asia to Anatolia contributed to the gene pool of the Turkish people and the role of the 11th-century settlement by Oghuz Turks. Some studies suggested that, although the Turks' settlement of Anatolia was of cultural importance, including the introduction of  the Turkish language and Islam, the genetic contribution from Central Asia may have been slight. A 2020 global study looking at whole-genome sequences showed that Turks have relatively lower within-population shared identical-by-descent genomic fragments compared to the rest of the world, suggesting mixture of remote populations. Some of the Turkic peoples originated from Central Asia may be related to the Xiongnu. Most (89%) of the Xiongnu sequences belong to Asian haplogroups, but nearly 11% belong to European haplogroups. Thus, contacts between European and Asian populations predated the Xiongnu culture, confirming results reported for two samples from  an early 3rd century B.C. Scytho-Siberian population. A study published in 2003 looked at Human leukocyte antigen genes to investigate the affinity of certain Mongolian tribes with Germans and Anatolian Turks. It was found that Germans and Turks were equally distant to the Mongolian populations. No close relationship was found between Turks and Mongolians despite the close relationship of their languages and shared historical neighborhood. A study of 75 individuals from various parts of Turkey concluded that the "genetic structure of the mitochondrial DNAs in the Turkish population bears some similarities to Turkic Central Asian populations". A 2001 study  comparing the populations of Mediterranean Europe and Turkic-speaking peoples of Central Asia estimated the Central Asian genetic contribution to current Anatolian Y-chromosome loci (one binary and six short tandem repeat) and mitochondrial DNA gene pool to be roughly 30%. A 2004 high-resolution SNP analysis of Y-chromosomal DNA in samples collected from blood banks, sperm banks, and university students in eight regions of Turkey found evidence for a weak but detectable signal (<9%) of gene flow from Central Asia. A 2006 study concluded that the true Central Asian contributions to Anatolia was 13% for males and  22% for females (with wide ranges of confidence intervals), and the language replacement in Turkey and might not have been in accordance with the elite dominance model. It was later observed that the male contribution from Central Asia to the Turkish population with reference to the Balkans was 13%. For all non-Turkic speaking populations, the Central Asian contribution was higher than in Turkey. According to the study, "the contributions ranging between 13%–58% must be considered with a caution because they harbor uncertainties about the state of pre-nomadic invasion and further local movements." In a 2015 study, Turkish samples  were in the West Eurasian clade which consisted of "all of mainland Europe, Sardinia, Sicily, Cyprus, western Russia, the Caucasus, Turkey, and Iran, and some individuals from Tajikistan and Turkmenistan." In this study, ancestry from East Asia was also visible in Turkish samples, with events after 1000 CE generally involving Asian sources being important when it comes to the ancestry of Turkey and its region. As of 2017, Central Asian genetic variation has been poorly studied, with little or no whole genome sequencing data for countries such as Turkmenistan and Afghanistan. Therefore, future comprehensive genome-wide studies are needed. Turkish  people, and other Western Asian populations, may also be closely related to Central Asian populations such as those near Western Asia. Haplogroup distributions. Cinnioğlu et al. (2004) found many Y-DNA haplogroups in Turkey. Most haplogroups in Turkey are shared with its West Asian and Caucasian neighbors. The most common haplogroup in Turkey is J2 (24%), which is widespread among Mediterranean, Caucasian, and West Asian populations. Haplogroups that are common in Europe (R1b and I; 20%), South Asia (L, R2, H; 5.7%), and Africa (A, E3*, E3a; 1%) are also present. By contrast, Central Asian haplogroups (C, Q, and O ) are rarer. However, the figure may rise to 36% if K, R1a, R1b, and L—which infrequently occur in Central Asia but are notable in many other Western Turkic groups—are included. J2 is also frequently found in Central Asia, a notably high frequency (30.4%) being observed among Uzbeks. The main percentages identified were as follows: Other markers that occurred in less than 1% are H, A, E3a, O, and R1*. Further research on Turkish Y-DNA groups. A 2008 study took into account oral histories and historical records. The researchers went to four settlements in Central Anatolia and chose  a random selection of subjects from among university students. In an Afshar village near Ankara where, according to oral tradition, the ancestors of the inhabitants came from Central Asia, the researchers found that 57% of the villagers had haplogroup L, 13% had haplogroup Q and 3% had haplogroup N. Examples of haplogroup L, which is most common in South Asia, might be a result of Central Asian migration even though the presence of haplogroup L in Central Asia itself was most likely a result of migration from South Asia. Therefore, Central Asian haplogroups potentially occurred in 73% of males in  the village. Furthermore, 10% of the Afshars had haplogroups E3a and E3b, while only 13% had haplogroup J2a, the most common in Turkey. By contrast, the inhabitants of a traditional Turkish village that had little migration had about 25% haplogroup N and 25% J2a, with 3% G and close to 30% R1 variants (mostly R1b). Whole genome sequencing. A whole-genome sequencing study of Turkish genetics, conducted on 16 individuals, concluded that the Turkish population forms a cluster with Southern European and Mediterranean populations and that the predicted contribution from ancestral East Asian populations (presumably reflecting a Central Asian origin ) is 21.7%. However, that does not provide a direct estimate of a migration rate, because of factors such as the unknown original contributing populations. The genetic variation of various populations in Central Asia "has been poorly characterized"; Western Asian populations may also be "closely related to populations in the east". Other studies. A 2001 study that looked at "HLA" alleles suggested that "Turks, Kurds, Armenians, Iranians, Jews, Lebanese and other (Eastern and Western) Mediterranean groups seem to share a common ancestry" and that historical populations such as Anatolian Hittite and Hurrian groups (older than 2000 B.C.) "may have given rise  to present‐day Kurdish, Armenian and Turkish populations." A 2004 study that looked at 11 human‐specific Alu insertion polymorphisms among Aromanians, North Macedonians, Albanians, Romanians, Greeks, and Turks, suggested a common ancestry for these populations. A 2011 study ruled out long-term and continuing genetic contacts between Anatolia and Siberia and confirmed the presence of significant mitochondrial DNA and Y-chromosome divergence between these regions, with minimal admixture. The research also confirmed the lack of mass migration and suggested that it was irregular punctuated migration events that engendered large-scale shifts in language and culture among Anatolia's diverse autochthonous inhabitants . A study in 2015, however, wrote, "Previous genetic studies have generally used Turks as representatives of ancient Anatolians. Our results show that Turks are genetically shifted towards Central Asians, a pattern consistent with a history of mixture with populations from this region." The authors found "7.9% (±0.4) East Asian ancestry in Turks from admixture occurring 800 (±170) years ago." According to a 2012 study of ethnic Turks, "Turkish population has a close genetic similarity to Middle Eastern and European populations and some degree of similarity to South Asian and Central Asian populations." The analysis modeled each person's DNA as  having originated from "K" ancestral populations and varied the parameter "K" from 2 to 7. At "K" = 3, comparing to individuals from the Middle East (Druze and Palestinian), Europe (French, Italian, Tuscan and Sardinian) and Central Asia (Uygur, Hazara and Kyrgyz), clustering results indicated that the contributions were 45%, 40% and 15% for the Middle Eastern, European and Central Asian populations, respectively. At "K" = 4, results for paternal ancestry were 38% European, 35% Middle Eastern, 18% South Asian, and 9% Central Asian. At "K" = 7, results of paternal ancestry were 77% European, 12% South Asian, 4% Middle  Eastern, and 6% Central Asian. However, results may reflect either previous population movements (such as migration and admixture) or genetic drift. The Turkish samples were closest to the Adygei population (Circassians) from the Caucasus; other sampled groups included European (French, Italian), Middle Eastern (Druze, Palestinian), and Central (Kyrgyz, Hazara, Uygur), South Asian (Pakistani), and East Asian (Mongolian, Han) populations. A study involving mitochondrial analysis of a Byzantine-era population, whose samples were gathered from excavations in the archaeological site of Sagalassos, found that these samples were closest to modern samples from "Turkey, Crimea, Iran and Italy (Campania and Puglia), Cyprus  and the Balkans (Bulgaria, Croatia, and Greece)." Modern-day samples from the nearby town of Ağlasun showed that lineages of East Eurasian descent assigned to macro-haplogroup M were found in the modern samples from Ağlasun. This haplogroup was significantly more frequent in Ağlasun (15%) than in Byzantine Sagalassos, but the study found "no genetic discontinuity across two millennia in the region." A 2019 study found that Turkish people cluster with Southern and Mediterranean Europe populations along with groups in the northern part of Southwest Asia (such as the populations from Caucasus, Northern Iraq, and Iranians). Another 2019 study found  that Turkish people have the lowest fixation index distances with Caucasus population group and Iranian-Syrian group, as compared to East-Central European, European (including Northern and Eastern European), Sardinian, Roma, and Turkmen groups or populations. The Caucasus group in the study included samples from Abkhazians, Adygey, Armenians, Balkars, Chechens, Georgians, Kumyks, Kurds, Lezgins, Nogays, and North Ossetians.