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Haplogroup O1b1a2a

O1b1a2a (O-M95 Southeast Asian major sublineage)

Macro-haplogroup

Parent clade

O1b1a2-M95

Formed (estimate)

c. 10,000–12,000 years before present

TMRCA (estimate)

c. 4,000–5,000 years ago

O1b1a2a

Overview

O1b1a2a is one of the principal downstream clades of O1b1a2-M95 and played a major role in shaping paternal ancestry across mainland Southeast Asia and parts of eastern India. The clade diverged during the mid-Holocene and contributed to the formation of agricultural communities associated with early Austroasiatic societies. Its demographic patterns suggest multiple founder effects tied to the expansion of rice farming and the emergence of settled Neolithic populations.

Geographic distribution

High frequencies in Cambodia, Laos, Vietnam and northeastern Thailand. Significant presence in Indian Munda populations, indicating prehistoric migration from Southeast Asia into India. Also found at moderate levels in Myanmar and Bangladesh.

Ancient DNA

Archaeogenetic evidence from Neolithic Vietnam indicates paternal ancestry upstream of O1b1a2a.
Expansion timing corresponds to the spread of early agriculture and pottery complexes in mainland Southeast Asia.
Munda populations in India show strong signatures of Southeast Asian paternal introgression aligned with M95 lineages.

Phylogeny & subclades

O1b1a2a forms a primary branch under M95 and is parallel to O1b1a2b. Its internal structure reflects repeated founder events in different parts of mainland Southeast Asia and island–mainland interface zones.

O1b1a2a*
Regional O-M95 derivatives

Notes & context