A · BT · CT · F · K · K2 · K2b · NO · O · O2 · O2-M122 · O2a-M324 · O2a2b1-M134 · O-M117 · O-M133
O2a2b1a1b-M133 (O-M133)
O-M133 is a major descendant branch of O-M117 and constitutes one of the principal components of modern East Asian paternal variation. It appears to have differentiated during the mid-Holocene among early agricultural communities in northern and central China. While numerically smaller than the O-F8 cluster, M133 still accounts for a substantial fraction of Y chromosomes in several Han and Sino-Tibetan populations.
M133 occurs in many Han Chinese populations, particularly in northern and central regions, and has been reported in Korea, Japan and Mongolia at moderate frequencies. It is also present in Tibeto-Burman groups and in certain Southeast Asian populations impacted by Chinese migration.
O-M133 is nested within the O-M117 tree as a distinct and relatively well-sampled lineage. It forms several downstream branches, some of which are concentrated in specific regions of China and Korea. Together with O-F8, it explains a large share of the internal structure of the M117 complex.
O-M133 refines the structure of O-M117 and provides additional resolution for East Asian paternal history, especially when distinguishing northern Chinese and Korean lineages from other M117-derived clusters.