In human genetics, Haplogroup O-M268, also known as O1b (formerly Haplogroup O2), is a Y-chromosome DNA haplogroup. Haplogroup O-M268 is a primary subclade of haplogroup O-F265, itself a primary descendant branch of Haplogroup O-M175.

Origin

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).

Distribution

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 O1b-P31 is also notable for the fact that it can be divided into two primary subclades that show almost completely disjunct distribution: O1b1-M1304/K18 and O1b2-M176/P49. One of these subclades, O1b1-M1304/K18 (also known as O-F2320), can be mainly divided into two subclades, O1b1a1-PK4 (formerly O2a) and O1b1a2-CTS4040 (formerly O2*(xM95,M176)). O1b1a1-PK4 is found mainly among populations of Southeast Asia and some tribal populations of India (such as the Remo, Juang, and Nicobarese), but it is also common among minority ethnic groups in southern China, and it is found with low frequency throughout China as well as in Japan. O1b1a2-CTS4040 is relatively rare and mainly distributed in East Asia, especially in China, where it accounts for approximately 3.22% of the national male population. The other primary subclade of Haplogroup O1b-P31, i.e. Haplogroup O1b2-M176 (formerly O2b), is found in approximately one third of present-day Japanese and Korean males and with low frequency (approximately 0.70% ) in Chinese males.

Phylogenetics

Phylogenetic History

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.

Original Research Publications

The following research teams per their publications were represented in the creation of the YCC Tree. • α and • β • γ • δ • ε • ζ • η

Phylogenetic Trees

This phylogenetic tree of haplogroup O subclades is based on the YCC 2008 tree and subsequent published research.

Genetics

• Genetic genealogy • Haplogroup • Haplotype • Human Y-chromosome DNA haplogroup • Molecular phylogenetics • Paragroup • Subclade • Y-chromosome haplogroups in populations of the world • Y-DNA haplogroups by ethnic group • Y-DNA haplogroups in populations of East and Southeast Asia

Y-DNA O Subclades

• O-47z • O-M101 • O-M113 • O-M117 • O-M119 • O-M121 • O-M122 • O-M134 • O-M159 • O-M162 • O-M164 • O-M175 • O-M176 • O-M50 • O-M7 • O-M88 • O-M95 • O-MSY2.2 • O-P31

Y-DNA Backbone Tree

Footnotes

Sources for conversion tables