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Haplogroup O1a2a

O1a2a (Island Southeast Asia Austronesian lineage)

Macro-haplogroup

Parent clade

O1a2

Formed (estimate)

c. 8,000–10,000 years before present

TMRCA (estimate)

c. 3,500–5,000 years ago

O1a2a

Overview

O1a2a is a major subbranch of O1a2 and forms one of the core paternal lineages of Island Southeast Asia. It diversified after the earliest movement of Austronesian speakers out of Taiwan, becoming especially common among early Philippine and Indonesian communities. Its formation corresponds to the consolidation of maritime settlements in the Batanes–Luzon–Sulawesi corridor and the rapid southward and eastward dispersals that followed.

Geographic distribution

O1a2a is common in the Philippines (Tagalog, Visayan, Ilocano), Indonesia (Sulawesi, Borneo, eastern Indonesia), Malaysia and Brunei. It also appears in Polynesia and Micronesia as part of later Austronesian radiation waves.

Ancient DNA

Ancient Southeast Asian remains show ancestry consistent with O1a2-level Neolithic migrants.
The timing of O1a2a diversification aligns with archaeological horizons marking early maritime networks in the Philippines and Indonesia.
Patterns of distribution reflect a rapid founder expansion followed by local diversification.

Phylogeny & subclades

O1a2a lies under the O1a2 branch and shows multiple downstream radiations across different islands of Southeast Asia, consistent with regional settlement waves and founder effects.

O1a2a*
Island-specific downstream branches

Notes & context