Haplogroup O-P31 (Y-DNA)

Haplogroup O-P31 Haplogroup O1b-P31_(O1b1-M1470,_O1b1a1-PK4,_O1b1a2-Pages59,_O1b2-M176) Distribution
Possible time of origin	30,100 [95% CI 27,800 <-> 32,400] ybp
Coalescence age	28,500 [95% CI 26,200 <-> 30,900] ybp
Ancestor	O-M175 > O-F265
Descendants	O-K18, O-M176
Defining mutations	P31, M268, L690/F167, F256/M1341, Y9038/FGC19644, L463/F330, M1461, F138, Y9317, FGC55566, F292/M1363, CTS4164, CTS6713/M1396, CTS5785/M1377, F435/M1417, F516, M1455
Highest frequencies	Austroasiatic-speaking peoples, Tai peoples, Hlai, Balinese, Javanese, Japanese, Ryukyuans, Koreans, Manchus, Malagasy

In human genetics, Haplogroup O-P31 is a Y-chromosome DNA haplogroup. Haplogroup O-P31 is a descendant branch of the greater Haplogroup O-M175.

In a paper published in 2011 by a group of Chinese researchers affiliated with Fudan University, it has been suggested that China is the origin of the expansion of haplogroup O-P31 (therein called Haplogroup O2-M268).

Haplogroup O-P31 is notable for the peculiarities of its geographical distribution. Like all clades of Haplogroup O-M175, Haplogroup O-P31 is found only among the males of modern Eastern Eurasian populations. However, Haplogroup O-P31 is generally found with high frequency only among certain populations, such as the Austroasiatic peoples of India, Bangladesh and Southeast Asia, the Nicobarese of the Nicobar Islands in the Indian Ocean, Koreans, and Japanese.

Besides its widespread and patchy distribution, Haplogroup O-P31 is also notable for the fact that it can be divided into two major subclades that show almost completely disjunct distribution. One of these subclades, Haplogroup O-M95, is found among some (mostly tribal) populations of South and Southeast Asia, as well as among the Japanese of Japan and the Balinese of Indonesia. The other major subclade, Haplogroup O-M176, is found almost exclusively among the Japanese, Koreans, and some Manchurians.

Prior to 2002, there were in academic literature at least seven naming systems for the Y-Chromosome Phylogenetic tree. This led to considerable confusion. In 2002, the major research groups came together and formed the Y-Chromosome Consortium (YCC). They published a joint paper that created a single new tree that all agreed to use. Later, a group of citizen scientists with an interest in population genetics and genetic genealogy formed a working group to create an amateur tree aiming at being above all timely. The table below brings together all of these works at the point of the landmark 2002 YCC Tree. This allows a researcher reviewing older published literature to quickly move between nomenclatures.