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.[1] 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.

Relevant links:

Y-DNA Haplogroup O and its Subclades - 2008
http://www.isogg.org/tree/ISOGG_HapgrpO08.html

Haplogroup O (Y-DNA) @ Wikipedia
"http://en.wikipedia.org/wiki/Haplogroup_O_(Y-DNA)"

Haplogroup O1 (Y-DNA) @ Wikipedia
"http://en.wikipedia.org/wiki/Haplogroup_O1_(Y-DNA)"

Haplogroup O2 (Y-DNA) @ Wikipedia
"http://en.wikipedia.org/wiki/Haplogroup_O2_(Y-DNA)"

Haplogroup O3 (Y-DNA) @ Wikipedia
"http://en.wikipedia.org/wiki/Haplogroup_O3_(Y-DNA)"

Y-Chromosome Evidence of Southern Origin of the East Asian–Specific Haplogroup O3-M122
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B8JDD-4RH3CKK-8&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=4cd3978a14f99eedc0bf0e98ce227c79

http://www.mediafire.com/?zj0ezmblmcd

As many Chinese belong to Haplogroup O, there is a sister group "China DNA" for those who have Chinese ancestry
http://www.facebook.com/group.php?gid=6831026431

China DNA Geographic Project @ Family Tree DNA
http://www.familytreedna.com/public/china

O...O3 Y-DNA Haplogroup Project @ Family Tree DNA
http://www.familytreedna.com/public/O3/
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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... (read more)