Overview
H1d is a rare but phylogenetically important branch of the H1 radiation, with its distribution centered on the Iranian plateau, eastern Iran, southern Turkmenistan and parts of Afghanistan. The lineage appears to represent an early Holocene expansion from South Asia into the Iranian highlands, followed by long term isolation and regional drift.
Although limited in global frequency, H1d contains unique SNP signatures that mark it as a distinct and stable paternal lineage. Its presence in populations historically connected with the eastern Iranian world suggests that H1d participated in early interactions along the Indo Iranian frontier. This makes H1d key for interpreting the deeper layers of paternal structure preceding later Indo Iranian expansions.
Geographic distribution
H1d occurs at low but measurable frequencies in eastern Iran, Sistan, Baluchistan, Khorasan and adjacent regions of Afghanistan, including Pashtun and Tajik populations. Occasional detections appear in Turkmenistan and Uzbekistan, typically in communities with historical southward connections.
In South Asia, H1d appears sporadically in Pakistan but is notably less common than H1a and H1b, suggesting that its center of gravity shifted westward early in its history.
Ancient DNA
- Several Chalcolithic Iranian genomes carry upstream H1 signatures consistent with H1d involvement.
- No confirmed H1d ancient sample exists yet, but the phylogeographic pattern strongly supports a deep presence in the Iranian plateau.
- Early Bronze Age material from southeast Iran shows potential upstream affinities.
Phylogeny & subclades
H1d forms the westernmost branch of the H1 radiation. It is phylogenetically marked by a set of derived SNPs distinct from both the South Asian centered H1b and the globally dispersing H1a. The structure of H1d is characterized by small microclades concentrated in the Iranian–Afghan highland corridor.
- H1d* basal
- Iranian plateau clusters
- Afghan highland microbranches
Notes & context
H1d adds structural and geographic completeness to the H1 tree. It captures one of the earliest westward expansions of H1 and preserves a demographic layer largely overshadowed by later migrations in the Iranian world.
References & external links