Overview
H1b is a major regional branch of the H1 radiation strongly associated with southern India, the Deccan plateau and Sri Lankan populations. It diverged early from the main H1 trunk and represents an ancient paternal layer that persisted through complex demographic transitions in southern South Asia. While less globally distributed compared to H1a, H1b retains considerable internal diversity and appears to reflect long term regional continuity.
H1b likely formed among early Holocene populations inhabiting peninsular India. Its distribution corresponds with archaeological evidence of early settled communities and the subsequent rise of southern Dravidian cultural spheres. Compared to H1a, H1b has fewer downstream branches with long distance dispersal, but it is deeply embedded in the demographic histories of southern Indian groups.
Geographic distribution
H1b is most common in southern India, particularly in Tamil Nadu, Karnataka, Andhra Pradesh and Kerala. It is also present in Sri Lanka and among several tribal groups of the Western Ghats and central Indian forested regions. The lineage has low but stable frequencies in Pakistan, reflecting earlier demographic layers.
In contrast to H1a, H1b is nearly absent from West Eurasia, Central Asia and Europe, underscoring its primarily South Asian footprint. Its distribution maps closely onto the geography of early southern Dravidian speaking populations, suggesting deep linguistic and demographic links.
Ancient DNA
- Chalcolithic and Iron Age South Asian genomes show upstream H1 signatures compatible with ancestral H1b.
- Ancient individuals from Deccan Neolithic sites sometimes display M52 associated lineages which may include early H1b representatives.
- No ancient Sri Lankan samples currently assigned to H1b, but modern continuity suggests deep local roots.
Phylogeny & subclades
Within H1, H1b forms a sister branch to H1a and sits upstream of several small microclades distributed across southern India. Its phylogeny is less deeply subdivided than H1a, but it retains a clear internal structuring with regionally distinctive clusters.
- H1b* basal
- Southern Indian H1b founder clusters
- Sri Lankan H1b microbranches
Notes & context
H1b is essential for capturing the full internal diversity of South Asian H1. Its distinct regional pattern provides strong contrast with the widespread H1a and highlights early demographic differentiation within the Indian subcontinent.
References & external links