Haplogroup K2b (Y-DNA)

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Haplogroup K2b (P331)

Haplogroup K2b is a branch of the Y-DNA family tree known as haplogroup K. It is estimated to be about 50,000 years old, a few thousand years younger than K, with researchers placing its origin somewhere in Asia (likely Southeast Asia, East Asia, or Central Asia). The ancient form of K2b that does not have any defining mutations (K2b*) has not been found in living men but was identified in the ancient Tianyuan man from China.

Two main sub-branches make up K2b:
- K2b1 (P397/P399): formerly called MS. This branch is strongly present in Southeast Asia and Oceania, including Papua New Guinea, the Philippines (notably the Aeta people), Melanesia, Indigenous Australians, and parts of Indonesia and Polynesia.
- P (K2b2; subclades include Q and R): also called P-P295 or P*, this branch is widespread across Europe, the Americas, Central Asia, South Asia, and Siberia. P1 (M45), the sub-branch of P (K2b2a), is the ancestor of Q and R and is younger than K2b by several thousand years.

Other notes:
- Basal K2b* is not found among living people but was identified in ancient remains.
- P* (P-P295*) is relatively rare today and is found mainly in Island Southeast Asia.
- There is evidence that K2b and its sister lineages diversified rapidly in Southeast Asia, followed by westward spread of P*, P1, Q, and R.
- Some geneticists, like Spencer Wells, suggest that the broader haplogroup K originated in the Middle East or Central Asia (around Iran or Pakistan).

Geographic patterns and frequencies:
- K2b1 is highly common in Melanesia and parts of Oceania; for example, Papua New Guinea shows very high frequencies of K2b1.
- In the Philippines, some indigenous groups (such as the Aeta) carry K2b1 and related P lineages.
- Indigenous Australians show substantial representation of K2b1 subclades.
- In Southeast Asia and nearby regions, P* and its subclades (including P1) appear in various populations, with Q and R spreading much more widely in Europe, the Americas, and parts of Asia.

In short, K2b splits into two major lines—K2b1 in Southeast Asia and Oceania, and P (with P1 giving Q and R) that spread across Europe, the Americas, and Asia. Its age and distribution reflect an early branching inside haplogroup K and a pattern of rapid diversification in Asia followed by later expansion into other regions.