B6*

Origins and Evolution

mtDNA haplogroup B6\* is a sublineage of macro-haplogroup B, a maternal branch that is widespread in East and Southeast Asia. Based on phylogenetic position and coalescence estimates for nearby B subclades, B6* is inferred to have arisen in the Late Pleistocene (around 18 kya) in continental East/Southeast Asia. As a starred designation (B6*), it denotes basal B6 lineages that do not carry downstream diagnostic mutations defining later subclades; such basal lineages frequently represent locally persistent maternal lineages with limited but detectable dispersal.

Subclades (if applicable)

By definition B6* denotes sequences assigned to B6 that lack clear downstream resolution into named subclades. Where deeper resolution is possible, B6 can split into more derived branches in some datasets, but many reported B6 sequences remain basal. This pattern — a modest number of basal B6 sequences alongside a small number of derived branches — is consistent with a history of localized persistence and occasional dispersal rather than a major continent-spanning demographic expansion.

Geographical Distribution

B6* is primarily recorded in mainland East Asia and mainland Southeast Asia, with additional low-frequency occurrences in island and coastal populations of Island Southeast Asia, Taiwan (Formosan groups), the Philippines, and some Near-Oceanic/Melanesian contexts. Frequencies are generally low to moderate at the population level, and the haplogroup is absent or extremely rare in much of South Asia and western Eurasia. The distribution pattern fits a model of a Late Pleistocene/early Holocene origin on the continental margins followed by participation in coastal and island dispersals, and later limited incorporation into Austronesian-associated migrations.

Historical and Cultural Significance

Although B6* is not a high-frequency marker for any large archaeological culture, its geographic signature links it to several important demographic processes in East and Southeast Asia:

• Pre-Neolithic coastal and maritime adaptations: The Late Pleistocene origin and coastal concentrations suggest B6 lineages were part of forager and early maritime networks along continental and island coasts.
• Neolithic and Holocene interactions: During the Holocene, B6 lineages may have been carried locally by expanding sedentary forager–farmer groups (for example, communities associated with early rice and horticultural economies in southern China and mainland Southeast Asia).
• Austronesian-era dispersals: The presence of B6 in Indigenous Taiwanese and scattered Austronesian-speaking island populations makes it a minor but informative component of the maternal ancestry involved in the broader Austronesian expansion; however, it appears as a secondary marker compared with higher-frequency Austronesian-associated mtDNA haplogroups (e.g., certain B4 sublineages).

Two documented ancient DNA occurrences (in the submitting database) indicate that B6 lineages have been present in archaeological contexts, supporting continuity of some maternal lineages through Holocene transitions in the region.

Conclusion

mtDNA B6* represents a localized, Late Pleistocene maternal lineage within macro-haplogroup B that highlights coastal and island population processes in East and Southeast Asia. Its low-to-moderate modern frequencies and presence in both continental and island contexts make it valuable for reconstructing regional demographic histories, particularly interactions between pre-Neolithic coastal populations, later Neolithic/bronze age agricultural expansions, and Austronesian maritime dispersals. Further deep sequencing and broader ancient DNA sampling will clarify internal B6 diversity and its precise roles in specific migratory episodes.