Haplogroup O, also known as O-M175, is a human Y-chromosome DNA haplogroup. It is primarily found among populations in Southeast Asia and East Asia. It also is found in various percentages of populations of the Russian Far East, Siberia, Central Asia, Caucasus, Crimea, Ukraine, Iran, South Asia, Oceania, Madagascar and the Comoros. Haplogroup O is a primary descendant of haplogroup NO-M214.

The O-M175 haplogroup is very common amongst males from East and Southeast Asia. It has two primary branches: O1 (O-F265) and O2 (O-M122). O1 is found at high frequencies amongst males native to Southeast Asia, Taiwan, the Japanese Archipelago, the Korean Peninsula, Madagascar and some populations in southern China and Austroasiatic speakers of India. O2 is found at high levels amongst Han Chinese, Tibeto-Burman populations (including many of those in Yunnan, Tibet, Burma, Northeast India, and Nepal), Manchu, Mongols (especially those who are citizens of the PRC), Koreans, Vietnamese, Filipinos, Japanese, Thais, Polynesians, Miao people, Hmong, the Naiman tribe of Kazakhs in Kazakhstan, Kazakhs in the southeast of Altai Republic, and Kazakhs in the Ili area of Xinjiang.

Origins Haplogroup O-M175 is a descendant haplogroup of Haplogroup NO-M214, and first appeared according to different theories either in Southeast Asia (see , , , and ) or East Asia (see ) approximately 40,000 years ago (or between 31,294 and 51,202 years ago according to Karmin et al. 2015).

Haplogroup O-M175 is one of NO-M214's two branches. The other is haplogroup N, which is common throughout North Eurasia.

Distribution This haplogroup appears in high to moderate frequencies in most populations in both East Asia and Southeast Asia, and it is almost exclusive to that region. It is almost nonexistent in Western Siberia, Western Asia, Europe, most of Africa, India and the Americas, where its presence may be the result of recent migrations. However, certain O subclades do achieve significant frequencies among some populations of Central Asia, South Asia, and Oceania. For example, one study found it at a rate of 67% among the Naimans, a tribe in Kazakhstan, even though the rate among Kazakhs in general is only about 3.3% to 10.8%.Maxat Zhabagin, Zhaxylyk Sabitov, Pavel Tarlykov, Inkar Tazhigulova, Zukhra Junissova, Dauren Yerezhepov, Rakhmetolla Akilzhanov, Elena Zholdybayeva, Lan-Hai Wei, Ainur Akilzhanova, Oleg Balanovsky, and Elena Balanovska, "The medieval Mongolian roots of Y-chromosomal lineages from South Kazakhstan." BMC Genetics 2020, 21(Suppl 1):87. https://doi.org/10.1186/s12863-020-00897-5 (It is notable that 75% of cases of haplogroup O-M175 observed in the Kazakh sample of Ashirbekov et al. 2017, of which 10.8% have been found to belong to haplogroup O-M175, have been contributed by the Naimans themselves; only 3.1% of the remainder of the Kazakh sample with the Naimans excluded belong to haplogroup O-M175.) Karafet et al. (2015) have assigned the Y-DNA of 46.2% (12/26) of a sample of Papuan from Pantar Island to haplogroup NO-M214; considering their location in the Southeast Archipelago, all or most of these individuals should belong to haplogroup O-M175.

An association with the spread of Austronesian languages in late antiquity is suggested by significant levels of O-M175 among island populations of the South Pacific and Indian Ocean, including the East African littoral. For example, Haplogroup O-M50 has even been found in Bantu-speaking populations of the Comoros along 6% of O-MSY2.2(xM50), while both O-M50 and O-M95(xM88) occur commonly among the Malagasy people of Madagascar with a combined frequency of 34%. O-M175 has been found in 28.1% of Solomon Islanders from Melanesia. 12% of Uyghurs , 6.8% of Kalmyks (17.1% of Khoshuud, 6.1% of Dörwöd, 3.3% of Torguud, 0% of Buzawa), 6.2% of Altaians , 4.1% of Uzbeks on average but Uzbeks from Bukhara 12.1%, Karakalpaks (Uzbekistan) 11.4%, Sinte (Uzbekistans) 6.7% and 4.0% of Buryats.

In the Caucasus region it has been found in the Nogais 6% but 5.3% in the Karan Nogais, it is also found in the Dargins of Dargwa speakers at 2.9%. In the Iranic population, it is found in Iranian (Esfahan) at 6.3% (), 8.9% of Tajiks in Afghanistan 4.2% in the Pathans in Pakistan () but 1% in Afghanistan, 3.1% in Burusho ().

Haplogroup O-M175 ranges in various moderate to high frequencies in the ethnic minorities of South Africa. The frequency of this haplogroup is 6.14% in the Cape colored population, 18% in Cape Coloured Muslim, 38% in Cape Indian Muslims and 10% in Cape Other Muslims. It's found 11.5% in the Réunion Creole.

Haplogroup O-M175 had also been found in Latin America and Caribbean as a result of massive Chinese male migration from the 19th century. It was found in the Jamaicans at 3.8%, and in Cubans, 1.5%.

Haplogroup O-M175 has been found in 88.7% of Asian American. 1.6% in Hispanic American, White Americans 0.5%, and 0.3% in African American. Another study gives 0.5% African American.

Among the sub-branches of haplogroup O-M175 are O-M119(O1a), O-M268(O1b), and O-M122(O2).

Among the ethnic groups of Khyber Pakhtunkhwa, Pakistan, Y Haplogroup O3-M122 makes up the majority of Jadoon's males at 76.32%. It was absent in the studied Sayyid (Syed) samples and appeared in low numbers among Tanolis (0.75%) , Gujars (0.81%) and Yousafzais (2.82%). There appears to be founder affect in the O3-M122 among the Jadoon.

Russians in China East Asian haplogroup O made up 58% of their Y haplogroup. O3-M122 specifically made up 47% of the Russian sample. The East Asian Y haplogroup O3-M122 was found in 47% of Russian males in China. In another test the East Asian paternal Y Haplogroup O made up 58% of Russian males samples in China.

Haplogroup O was found in 1%-1.2% of Persians in one sample.

O3-M122 is the commonly shared genetic signature of Sino-Tibetan speaking ethnicities.

O-M175* A broad survey of Y-chromosome variation among populations of central Eurasia found haplogroup O-M175(xM119,M95,M122) in 31% (14/45) of a sample of Koreans and in smaller percentages of Crimean Tatars (1/22 = 4.5%), Tajiks (1/16 = 6.25% Dushanbe, 1/40 = 2.5% Samarkand), Uyghurs (2/41 = 4.9%), Uzbeks (1/68 = 1.5% Surxondaryo, 1/70 = 1.4% Xorazm), and Kazakhs (1/54 = 1.9%) . However, nearly all of the purported Korean O-M175(xM119,M95,M122) Y-chromosomes may belong to Haplogroup O-M176,O-M175(xM119,M95,M122) is sometimes incorrectly called "O*". and later studies do not support the finding of O-M175* among similar population samples (, ). The reported examples of O-M175(xM119,M95,M122) Y-chromosomes that have been found among these populations might therefore belong to Haplogroup O-M268*(xM95,M176) or Haplogroup O-M176 (O1b2).

A study published in 2013 found O-M175(xM119, M95, M176, M122) Y-DNA in 5.5% (1/18) Iranians from Teheran, 5.4% (2/37) Tajiks from Badakhshan Province of Afghanistan, and 1/97 Mongols from northwest Mongolia, while finding O-M176 only in 1/20 Mongols from northeast Mongolia.

O-F265 (O1) O1a-M119 and O1b-M268 share a common ancestor, O1-F265 (a.k.a. O-F75) approximately 33,181 (95% CI 24,461 to 36,879) YBP. O1-F265, in turn, coalesces to a common ancestor with O2-M122 approximately 33,943 (95% CI 25,124 to 37,631) YBP. Thus, O1-F265 should have existed as a single haplogroup parallel to O2-M122 for a duration of approximately 762 years (or anywhere from 0 to 13,170 years considering the 95% CIs and assuming that the phylogeny is correct) before breaking up into its two extant descendant haplogroups, O1-MSY2.2 and O1b-M268.

O-M119 (O1a)

O-M119 (which was known briefly as O-MSY2.2, until the SNP MSY2.2 was found to be unreliable) is found frequently in Austronesian-speaking people, with a moderate distribution in southern and eastern Chinese and Kra-Dai peoples.

O-M268 (O1b)

O-K18 NaxiYFull Haplogroup YTree v5.04 at 16 May 2017 O-CTS4040 O-MF56251 Observed sporadically in China (Guangxi, Guangdong, Sichuan, Zhejiang, Jiangsu, Beijing), Thailand (Phuan, Yuan, Central Thai), Vietnam (Nùng, Tày) O-Page59/CTS10887 Found among North Han Chinese (5%), East Han Chinese (4%), South Han Chinese (3%) O-F4070 O-MF106398 Observed sporadically in China (Guangdong, Henan, Hubei, Jiangxi, Sichuan, Zhejiang, Guangxi, Heilongjiang, Jiangsu, Shandong) O-F779/F993/F3135 China, Vietnam (Lahu), QatarO Y-Haplogroup Project at Family Tree DNA O-MF107014 Observed sporadically in China (Jiangsu, Anhui, Heilongjiang) O-CTS5160/MF61620 China (Han, mostly Guangdong or Fujian) O-F2064/F1759 China (Han from Fujian, Shandong), Singapore, Vietnam (Sila, Hanhi, Kinh), Korea O-PH2797/CTS1127 China (especially Shandong, Jiangsu, Liaoning, Hebei, Anhui, Beijing, Henan, and Shanghai) O-MF66989 Observed sporadically in China (Zhejiang, Guizhou, Hebei, Jiangsu, Shanghai, Shanxi) O-PH2506 China (Beijing), Japan O-Y148532 China (Shandong, Heilongjiang, Liaoning, Jilin, Jiangsu, Shanghai, Sichuan, Beijing, Shaanxi), Afghanistan (Hazara) O-Y239146/MF31164 Singapore, Taiwan O-Y47392/MF17288 China (Zhejiang) O-BY182144/Y157814 China (Shandong, Gansu), Taiwan O-MF16472/MF148514 China (Guangdong, Shandong, Henan, Beijing, Hunan, Jiangsu, etc.) O-MF184575 China (Zhejiang, Jiangxi, Guangxi, Sichuan, Jiangsu, Shandong, Inner Mongolia, Jilin Korean) O-ACT3266/Y149401 China (Shandong, Jiangsu) O-PH4822 China (Beijing, Jiangsu) O-F417/M1654/CTS469 Japan (Tokyo) O-F840/F1247/F1378 O-Y185784 Singapore O-CTS250 O-F2760 China (Beijing, Dai) O-FGC30081 China (Hubei, Guangdong) O-CTS1451 Korea, China (Hubei, Shandong, Sichuan, Jiangxi, Hunan, Jiangsu, Chongqing, Guangdong, Anhui, Hebei, Henan, Beijing, etc.) O-CTS9996/PF4341 Philippines O-PF4341* Hunan (Han) O-CTS298 China (esp. Jiangsu, Shandong, Henan, Anhui, Shanghai, and Liaoning) O-F16308 China (esp. Hunan) O-MF2931 China (esp. Zhejiang) O-MF14344 China (esp. Shaanxi and Anhui) O-F1356 China (Shandong, Beijing), Vietnam (Kinh from Ho Chi Minh City), South Korea O-PK4 O-F838 Found in about 1.4% of Han Chinese (and esp. in Hunan, Chongqing, Jiangxi, Sichuan, Guizhou) O-CTS3857 O-F714 O-F2081 Shaanxi (Han) O-F3357 O-F977 Liaoning O-F1199 Beijing, Sichuan O-ACT7133 Chongqing Liwutu, Jiangxi O-Y168698 Sichuan, Anhui O-CTS4052/CTS5664 Hunan (Han) O-Y155291 Anhui , medieval Turk (fl. ca. 600 - 900 CE) from the oasis of Otrar O-CTS2452 Guangxi, Hunan O-F15640/F11242 Fujian, Singapore, Spain (Burgos) O-F16212 O-F21414 Fujian O-F15452 O-F15300 Chongqing, Guizhou, Anhui O-F14826 Hunan [Yong zhou Tang family] O-MF45275 Guangxi O-Y34152 O-MF43808 Sichuan, Hunan O-MF37500 Hunan O-MF43192 Sichuan, Hunan O-M95 O-CTS350 China (Ningxia, Yunnan, Heilongjiang, Hunan, Shaanxi, Anhui, etc.) O-CTS350* Japan (Aichi) O-CTS10007/CTS926 China (esp. Hunan and Guangdong) O-M1310 O-Y172653/Y172877 Found in China (esp. Zhejiang, Fujian, Guangdong, Sichuan, Hunan, Jiangxi, Hubei, Chongqing) and Japan O-F1803/M1348 China (Zhejiang, Shandong, Beijing, Guangdong, Hubei, Sichuan, Jiangsu, Shanghai, etc.) O-ACT721/ACT1038 Found sporadically in China (Zhejiang, Anhui, Hunan, Hainan, Tianjin, Beijing, Liaoning, Heilongjiang) O-F789/M1283 Found in China (Blang, Palaung, Wa, Dai, Yi, Naxi), Vietnam, Cambodia, Singapore (Malay), Java, Borneo, Thailand, Laos, Myanmar, Bhutan, Bangladesh, India (Tripura, Ho, Konda Dora, Gond) O-M1283* Lao Isan O-MF600645 Gansu (Hui, Dongxiang), Sichuan (Chengdu), Hunan (Yiyang) O-M1368 Singapore O-M1361 O-MF611153 Found sporadically in China (Hunan, Hubei, Chongqing, Guangxi, Jiangxi) O-A22938 Vietnam (Kinh from Ho Chi Minh City), China (Hong Kong, Qinzhou, Chongqing, Lijiang) O-F2194 China (esp. Guangxi, with a few members in Yunnan, Chongqing, Hubei, etc.) O-BY189914 China (mostly Guangdong, Guangxi) O-F16163 China (Guangdong, Sichuan, Hubei, etc.), Taiwan O-F20644 China (Guangxi, Yunnan, Guangdong, Gansu, Hunan, Sichuan, etc.)