The nations which make up Central Asia are five of the former Soviet republics: Kazakhstan, Kyrgyzstan, Turkmenistan, Tajikistan, and Uzbekistan, which have a total population of about . Afghanistan is not always considered part of the region, but when it is, Central Asia has a total population of about 122 million (2016); Mongolia and Xinjiang (part of China) is also sometimes considered part of Central Asia due to its Central Asian cultural ties and traditions, although geographically it is East Asian. Most central Asians belong to religions which were introduced to the area within the last 1,500 years, such as Sunni Islam, Shia Islam, Ismaili Islam, Tengriism, and Syriac Christianity (mostly East Syriac). Buddhism, however, was introduced to Central Asia over 2,200 years ago, and Zoroastrianism, over 2,500 years ago.

Ethnic groups

The below are demographic data on the ethnic groups in Central Asia. Ethnic groupCenter of population in Central AsiaTotal roughly estimated population in Central AsiaUzbekUzbekistan, Afghanistan, Tajikistan, Kyrgyzstan, Turkmenistan, Kazakhstan36,000,000TajikTajikistan, Uzbekistan and Afghanistan. It includes the Pamiri people, who are officially categorized as Tajiks in Tajikistan.25,000,000KazakhKazakhstan, Uzbekistan17,500,000UyghurNorthwest China, Eastern Kazakhstan, Uzbekistan, Kyrgyzstan13,000,000PashtunAfghanistan12,500,000Dungan or HuiNorthwest China, Kyrgyzstan10,500,000HazaraAfghanistan6,500,000TurkmenTurkmenistan, Afghanistan, Iran6,500,000KyrgyzKyrgyzstan4,900,000RussiansKazakhstan, Uzbekistan, Kyrgyzstan3,700,000MongoliansMongolia, Kyrgyzstan3,237,000AimakCentral and Northwest Afghanistan1,500,000TatarsUzbekistan700,000BalochSouthern Afghanistan, Turkmenistan600,000KOKAISLOVÁ, Pavla, KOKAISL Petr. Ethnic Identity of The Baloch People. Central Asia and The Caucasus. Journal of Social and Political Studies. Volume 13, Issue 3, 2012, p. 45-55., ISSN 1404-6091KarakalpaksNorth western Uzbekistan500,000KoreansKazakhstan, Uzbekistan500,000Alekseenko, Aleksandr Nikolaevich (2000). Республика в зеркале переписей населения [Republic in the Mirror of the Population Censuses] (PDF). Population and Society: Newsletter of the Centre for Demography and Human Ecology (in Russian). Institute of Economic Forecasting of the Russian Academy of Sciences (47): 58–62. Retrieved 18 March 2019.UkrainiansNorthern Kazakhstan250,000NuristanisFar eastern and northern Afghanistan200,000+Meskhetian TurksKazakhstan200,000Volga GermansKazakhstan200,000BelarusiansNorthern Kazakhstan100,000–200,000ArmeniansTurkmenistan, Uzbekistan100,000AzeriKazakhstan, Turkmenistan 100,000PolesNorthern Kazakhstan50,000–100,000ChechensKazakhstan 40,000ChuvashNorthern Kazakhstan35,000BashkirsKazakhstan30,000GreeksKazakhstan 30,000MoldovansKazakhstan 25,000MordvinsKazakhstan20,000RomaniansKazakhstan 20,000IndiansKazakhstan, Kyrgyzstan19,500AltaiNorthern Kazakhstan10,000ArabsUzbekistan, Tajikistan10,000Bukharian JewsUzbekistan1,500

Genetic history

An analysis of Scytho-Siberian matrilineal DNA lineages of Iron Age human remains from the Altai region found evidence of a mixture of West Eurasian and East Asian maternal lineages. "Studies on ancient mitochondrial DNA of this region suggest that the Altai Mountains played the role of a geographical barrier between West and East Eurasian lineages until the beginning of the Iron Age. After the 7th century BC, coinciding with Scythian expansion across the Eurasian steppes, a gradual influx of East Eurasian sequences in Western steppes is detected. However, the underlying events behind the genetic admixture in Altai during the Iron Age are still unresolved: 1) whether it was a result of migratory events (eastward firstly, westward secondly), or 2) whether it was a result of a local demographic expansion in a 'contact zone' between European and East Asian people. In the present work, we analyzed the mitochondrial DNA lineages in human remains from Bronze and Iron Age burials of Mongolian Altai" Prior to the Iron Age, all ancient maternal lineages in the Altai region were of West Eurasian origin, however Iron Age specimens show that Western Eurasian lineages were reduced by 50%, and East Asian lineages increased by 50%. The authors suggested that the rise of East Asian mtDNA lineages likely happened within the Iron Age Scythian period.

The ancestry of modern Central Asian populations is significantly derived from later Indo-Iranian and Turkic populations.

A genetic study published in Nature in May 2018 examined the remains of four elite Türk soldiers buried between ca. 300 AD and 700 AD. 50% of the samples of Y-DNA belonged to the West Eurasian haplogroup R1, while the other 50% belonged to East Eurasian haplogroups Q and O. The extracted samples of mtDNA belonged mainly to East Eurasian haplogroups C4b1, A14 and A15c, while one specimen carried the West Eurasian haplogroup H2a. The authors suggested that Central Asian nomadic populations may have been Turkicized by East Asian elite minorities, resulting in a small but detectable increase in East Asian ancestry. However, these authors also found that Türkic period individuals were extremely genetically diverse, with some individuals being of near complete West Eurasian descent. To explain this diversity of ancestry, they propose that there were also incoming West Eurasians moving eastward on the Eurasian steppe during the Türkic period, resulting in admixture.

A 2020 study analyzed genetic data from 7 early medieval Türk skeletal remains from Eastern Turkic Khaganate burial sites in Mongolia. The authors described the Türk samples as highly diverse, carrying on average 40% West Eurasian, and 60% East Eurasian ancestry. West Eurasian ancestry in the Türks combined Sarmatian-related and BMAC ancestry, while the East Eurasian ancestry was related to Ancient Northeast Asians. The authors also observed that the Western Steppe Herder ancestry in the Türks was largely inherited from male ancestors, which also corresponds with the marked increase of paternal haplogroups such as R and J during the Türkic period in Mongolia. Admixture between East and West Eurasian ancestors of the Türkic samples was dated to 500 CE, or roughly 8 generations prior. Three of the Türkic-affiliated males carried the paternal haplogroups J2a and J1a, two carried haplogroup C-F3830, and one carried R1a-Z93. The analyzed maternal haplogroups were identified as D4, D2, B4, C4, H1 and U7.

Mongolians derive most of their ancestry from Ancient Northeast Asians (82–94%), with a variable amount of West Eurasian admixture (6-18%) from a Bronze Age Western Steppe Herder source, with Mongolians from Inner Mongolia having higher Ancient Northeast Asian component than Mongolians from Mongolia. Kazakhs derive around 60% of their ancestry from Eastern Eurasians and around 40% from Western Eurasians. pp. 5-11: "Chinese Kazakhs shared significant more alleles with West Eurasians than any other Mongolian groups. We here confirm the genetic substructure within three Mongolian groups and Chinese Kazakhs was caused by the different amounts of West Eurasian related admixture in them." "We showed that there are genetic substructures within Mongolians corresponding to Ölöd, Chahar, and Inner Mongolian clusters, which is consistent with their tribe classifications. The substructure is shaped by the relatedness of Mongolians to West Eurasians. Mongolians and Kazakhs are on a genetic cline in terms of different proportions of West Eurasian related admixture from 6% to 40%. The genetic source for the West Eurasian ancestry was most likely Bronze Age Steppe population-related. We note that the small number of sampled individuals from different tribes is a limitation of the study. However, our findings are consistent with archaeological and ancient genomic evidence that the Bronze Age Steppe populations shaped the culture and genetic makeup of northern Eurasia through rapid expansion (Allentoft et al., 2015)." Other studies model Kazakhs and Kyrgyz as a mixture of "Xinj_HE3"-related (44.8–58.9%) and "Mongolia_Xiongnu_o1"-related ancestries (41.1–55.2%), with the former component being ANE-rich. Uyghurs, Uzbeks and Turkmens can likewise be modeled as a mixture of "Turkmenistan_IA"-related (48.8–65.1%) and "Mongolia_Xiongnu_o1"-related (34.9–51.2%) components. Tajiks can be modeled as a mixture of Iranian farmer-related (43.8–52.8%), ANE-related(13.3–15.8%), Western European hunter-gatherer-related (9.5–11.8%), Baikal hunter-gatherer-related (7.7–17.1%), and Anatolian farmer-related (9.7–15.6%) ancestries. Some input from Andamanese-related groups is also detected. "The major ancestry components in the Kyrgyz are from Baikal hunter-gatherer (i.e., Russia_Shamanka_Eneolithic; 59.3–69.8%) and Iranian farmer–related ancestries (16–23.8%). The remaining minor ancestry components are from Anatolian farmers (5.1–5.6%), Western European hunter-gatherers (5.3–6.6%) and ANE-related Tarim_EMBA1 (3.2–5.3%). The ancestry profiles of Tajik populations can be dissected into five components from related ancestries of Iranian farmer (43.8–52.8%), ANE (13.3–15.8%), Western European hunter-gatherer (9.5–11.8%), Baikal hunter-gatherer (7.7–17.1%), and Anatolian farmer (9.7–15.6%)."

A 2022 study stated that modern Central Asians can be divided into Indo-Iranian and Turko-Mongol groups; Indo-Iranian groups formed through admixture between local BMAC and Andronovo-related populations near the end of the Bronze Age and early Iron Age, coinciding with the end of the Oxus Civilization. They are also closely related to Iron Age Turkmenistan individuals, who have a mixture of Western Scandinavian Hunter-Gatherers/Eastern European Hunter-Gatherer (25%), Iranian Neolithic (30%) and Anatolian Farmer (35%) ancestries. Modern Indo-Iranian groups are largely continuous with these ancient groups but received some East Asian-related ancestry, represented by Baikal Hunter-Gatherer ancestry, from Turko-Mongol groups and South Asian-related ancestry, especially for Tajiks, after the Iron Age. Modern Turko-Mongol groups, in contrast, descend from Iron Age migrants to Central Asia and vary in their affinities to Indo-Iranian and ancient Baikal groups but on average, they receive 50% of their ancestry from Baikal Hunter-Gatherers and to a lesser extent, Han-related sources. Overall, the modern Yaghnobis can be used as proxies for the pre-Iron Age Indo-Iranian substrate although they received some Baikal Hunter-Gatherer ancestry that was absent in pre-Iron Age Central Asians.

Religion