Haplogroup K2, also known as K-M526 and formerly known as K(xLT) and MNOPS, is a human Y-DNA haplogroup. Relative to its age, the internal structure of K2 is extremely complex, and subclades of it are carried by males native to regions including Australasia, Oceania, Southeast Asia, South Asia, East Asia, Central Asia, the Americas, Europe, and the Horn of Africa. Many of its branches are very common, the most numerically important being R in Europe and South Asia and O in East and Southeast Asia (as well as recent immigrants to other continents). Haplogroups N and Q, while they are less common overall, are also very widespread, in northern Eurasia and the Americas respectively. M and S are almost entirely restricted to Oceania and eastern Indonesia, where they occur at high frequency.