Haplogroup O (Y-DNA)
In human genetics, Haplogroup O (M175) is a Y-chromosome DNA haplogroup.
This haplogroup appears in 80-90% of all men in East and Southeast Asia, and it is almost exclusive to that region: M175 is almost nonexistent in Western Siberia, Western Asia, and Europe and is completely absent from Africa and the Americas, although certain clades of Haplogroup O do achieve significant frequencies among some tribal populations of South Asia, Altaic-speaking populations of Central Asia, and Austronesian-speaking populations of Oceania.
Haplogroup O is a descendant haplogroup of Haplogroup NO (M214), and is believed to have first appeared in Siberia or eastern Central Asia approximately 35,000 years ago. Haplogroup O shares a node in the phylogenetic tree of human Y-chromosomes with Haplogroup N, which is common throughout North Eurasia.
Among the subbranches of Haplogroup O are Haplogroup O1, Haplogroup O2, and Haplogroup O3. Haplogroup O- lineages, which belong to Haplogroup O but do not display any of the later mutations that define the major subclades O1, O2, and O3, can still be detected at a low frequency among most modern populations of Central Asia and East Asia. For example, a broad survey of Y-chromosome variation among populations of central Eurasia found haplogroup O-M175*(xO1a-M119,O2a-M95,O3-M122) in 2.5% (one out of 40 individuals) of a sample of Tajiks in Samarkand, 4.5% (1/22) of Crimean Tatars in Uzbekistan, 1.5% (1/68) of Uzbeks in Surkhandarya, 1.4% (1/70) of Uzbeks in Khorezm, 6.3% (1/16) of Tajiks in Dushanbe, 1.9% (1/54) of Kazakhs in Kazakhstan, 4.9% (2/41) of Uyghurs in Kazakhstan, and 31.1% (14/45) of Koreans. However, approximately 30% of all Korean O*(xO1a,O2a,O3) Y-chromosomes probably belong to Haplogroup O2b, which has been found to be very common among Koreans. There is also a possibility that the so-called Haplogroup O- Y-chromosomes that have been found among these populations might belong to Haplogroup O1*(xO1a-M119), Haplogroup O2*(xO2a-M95,O2b-M176), or Haplogroup O2b-M176.

# Subgroups
The subclades of Haplogroup O with their defining mutation, according to the 2006 ISOGG tree:
- O (M175)
O*
O1 (MSY2.2)
O1*
O1a (M119) Typical of Austronesians, southern Han Chinese, and Tai-Kadai peoples
O1a*
O1a1 (M101)
O1a2 (M50, M103, M110)
O2 (P31, M268)
O2*
O2a (M95) Typical of Austro-Asiatic peoples, Tai-Kadai peoples, Malays, and Indonesians, with a moderate distribution throughout South Asia, Southeast Asia, East Asia, and Central Asia
O2a*
O2a1 (M88, M111) Frequently found among Hani, Tai peoples, Cambodians, and Vietnamese, with a moderate distribution among Qiang, Yi, Hlai, Yao, Taiwanese aborigines, and Han Chinese of Sichuan, Guangxi, and Guangdong
O2a1*
O2a1a (PK4) Found at low frequency among Pashtuns
O2a2 (M297)
O2b (SRY465 (M176))
O2b*
O2b1 (P49) Typical of Koreans
O2b1*
O2b1a (47z) Typical of Japanese and Ryukyuans
O3 (M122) Typical of populations of East Asia, Southeast Asia, and culturally Austronesian regions of Oceania, with a moderate distribution in Central Asia
O3*
O3a (M324)
O3a*
O3a1 (M121, DYS257)
O3a2 (M164)
O3a3 (LINE1, M159) Found at low to moderate frequency throughout East Asia and Southeast Asia, especially among Hmong-Mien peoples and Han Chinese
O3a4 (M7) Typical of Hmong-Mien peoples
O3a4*
O3a4a (M113, M188, M209)
O3a4a*
O3a4a1 (N4)
O3a4a2 (N5)
O3a5 (M134) Typical of Sino-Tibetan peoples, with a moderate distribution throughout East Asia and Southeast Asia
O3a5*
O3a5a (M117, M133) Typical of Han Chinese and Tibetans, with a moderate distribution throughout East Asia
O3a5a*
O3a5a1 (M162)
O3a5b (P101)
O3a6 (M300)
O3a7 (M333)
- O*
- O1 (MSY2.2)
O1*
O1a (M119) Typical of Austronesians, southern Han Chinese, and Tai-Kadai peoples
O1a*
O1a1 (M101)
O1a2 (M50, M103, M110)
- O1*
- O1a (M119) Typical of Austronesians, southern Han Chinese, and Tai-Kadai peoples
O1a*
O1a1 (M101)
O1a2 (M50, M103, M110)
- O1a*
- O1a1 (M101)
- O1a2 (M50, M103, M110)
- O2 (P31, M268)
O2*
O2a (M95) Typical of Austro-Asiatic peoples, Tai-Kadai peoples, Malays, and Indonesians, with a moderate distribution throughout South Asia, Southeast Asia, East Asia, and Central Asia
O2a*
O2a1 (M88, M111) Frequently found among Hani, Tai peoples, Cambodians, and Vietnamese, with a moderate distribution among Qiang, Yi, Hlai, Yao, Taiwanese aborigines, and Han Chinese of Sichuan, Guangxi, and Guangdong
O2a1*
O2a1a (PK4) Found at low frequency among Pashtuns
O2a2 (M297)
O2b (SRY465 (M176))
O2b*
O2b1 (P49) Typical of Koreans
O2b1*
O2b1a (47z) Typical of Japanese and Ryukyuans
- O2*
- O2a (M95) Typical of Austro-Asiatic peoples, Tai-Kadai peoples, Malays, and Indonesians, with a moderate distribution throughout South Asia, Southeast Asia, East Asia, and Central Asia
O2a*
O2a1 (M88, M111) Frequently found among Hani, Tai peoples, Cambodians, and Vietnamese, with a moderate distribution among Qiang, Yi, Hlai, Yao, Taiwanese aborigines, and Han Chinese of Sichuan, Guangxi, and Guangdong
O2a1*
O2a1a (PK4) Found at low frequency among Pashtuns
O2a2 (M297)
- O2a*
- O2a1 (M88, M111) Frequently found among Hani, Tai peoples, Cambodians, and Vietnamese, with a moderate distribution among Qiang, Yi, Hlai, Yao, Taiwanese aborigines, and Han Chinese of Sichuan, Guangxi, and Guangdong
O2a1*
O2a1a (PK4) Found at low frequency among Pashtuns
- O2a1*
- O2a1a (PK4) Found at low frequency among Pashtuns
- O2a2 (M297)
- O2b (SRY465 (M176))
O2b*
O2b1 (P49) Typical of Koreans
O2b1*
O2b1a (47z) Typical of Japanese and Ryukyuans
- O2b*
- O2b1 (P49) Typical of Koreans
O2b1*
O2b1a (47z) Typical of Japanese and Ryukyuans
- O2b1*
- O2b1a (47z) Typical of Japanese and Ryukyuans
- O3 (M122) Typical of populations of East Asia, Southeast Asia, and culturally Austronesian regions of Oceania, with a moderate distribution in Central Asia
O3*
O3a (M324)
O3a*
O3a1 (M121, DYS257)
O3a2 (M164)
O3a3 (LINE1, M159) Found at low to moderate frequency throughout East Asia and Southeast Asia, especially among Hmong-Mien peoples and Han Chinese
O3a4 (M7) Typical of Hmong-Mien peoples
O3a4*
O3a4a (M113, M188, M209)
O3a4a*
O3a4a1 (N4)
O3a4a2 (N5)
O3a5 (M134) Typical of Sino-Tibetan peoples, with a moderate distribution throughout East Asia and Southeast Asia
O3a5*
O3a5a (M117, M133) Typical of Han Chinese and Tibetans, with a moderate distribution throughout East Asia
O3a5a*
O3a5a1 (M162)
O3a5b (P101)
O3a6 (M300)
O3a7 (M333)
- O3*
- O3a (M324)
O3a*
O3a1 (M121, DYS257)
O3a2 (M164)
O3a3 (LINE1, M159) Found at low to moderate frequency throughout East Asia and Southeast Asia, especially among Hmong-Mien peoples and Han Chinese
O3a4 (M7) Typical of Hmong-Mien peoples
O3a4*
O3a4a (M113, M188, M209)
O3a4a*
O3a4a1 (N4)
O3a4a2 (N5)
O3a5 (M134) Typical of Sino-Tibetan peoples, with a moderate distribution throughout East Asia and Southeast Asia
O3a5*
O3a5a (M117, M133) Typical of Han Chinese and Tibetans, with a moderate distribution throughout East Asia
O3a5a*
O3a5a1 (M162)
O3a5b (P101)
O3a6 (M300)
O3a7 (M333)
- O3a*
- O3a1 (M121, DYS257)
- O3a2 (M164)
- O3a3 (LINE1, M159) Found at low to moderate frequency throughout East Asia and Southeast Asia, especially among Hmong-Mien peoples and Han Chinese
- O3a4 (M7) Typical of Hmong-Mien peoples
O3a4*
O3a4a (M113, M188, M209)
O3a4a*
O3a4a1 (N4)
O3a4a2 (N5)
- O3a4*
- O3a4a (M113, M188, M209)
O3a4a*
O3a4a1 (N4)
O3a4a2 (N5)
- O3a4a*
- O3a4a1 (N4)
- O3a4a2 (N5)
- O3a5 (M134) Typical of Sino-Tibetan peoples, with a moderate distribution throughout East Asia and Southeast Asia
O3a5*
O3a5a (M117, M133) Typical of Han Chinese and Tibetans, with a moderate distribution throughout East Asia
O3a5a*
O3a5a1 (M162)
O3a5b (P101)
- O3a5*
- O3a5a (M117, M133) Typical of Han Chinese and Tibetans, with a moderate distribution throughout East Asia
O3a5a*
O3a5a1 (M162)
- O3a5a*
- O3a5a1 (M162)
- O3a5b (P101)
- O3a6 (M300)
- O3a7 (M333)