Overview
G1a4 (Z4494) is a fairly rare downstream branch of G1a that appears concentrated in the eastern Iranian Plateau, Afghanistan and parts of northern Pakistan. It represents a mid-Holocene radiation, younger than the principal Iranian-centered lineages of G1a1 and G1a2 but older than the very recent tribal expansions found in some G1a3 descendants. Its demographic profile suggests association with early Indo-Iranian cultural formations during the Late Bronze and Early Iron Age, though its roots lie firmly in earlier Iranian Plateau populations.
G1a4’s phylogeographic footprint aligns with mountainous and foothill environments—regions that historically sustained agro-pastoralist communities whose paternal lines often underwent localized founder effects. Although numerically small, this lineage is a crucial component of the deeper G1a structure, bridging early Iranian ancestry with later ethno-linguistic expansions across eastern Iran and the Afghan highlands.
Geographic distribution
Modern G1a4 concentrations appear in eastern Iran (Khorasan region), Afghanistan (Herat, Badghis, parts of Ghazni), and northwest Pakistan. Occasional lineages occur among Tajiks, Uzbeks and Turkmen populations. Minimal presence in the Caucasus suggests only limited westward historical movement.
Ancient DNA
- Late Bronze Age remains from eastern Iran occasionally show SNP patterns consistent with proto-G1a4 ancestry.
- Iron Age individuals in Afghanistan and Bactria show upstream variants potentially ancestral to G1a4.
- No evidence of G1a4 appears in early Holocene or Neolithic Near Eastern genomes, consistent with its relatively young age.
Phylogeny & subclades
G1a4 forms several tightly grouped WGS-defined subclusters, generally tied to Afghan and eastern Iranian population isolates. Its branching pattern indicates a rapid mid-Holocene divergence followed by multiple local founder effects typical of small agro-pastoralist groups. It sits phylogenetically between the broader Iranian–Central Asian expansions of G1a2 and the more regionally concentrated G1a3.
- G1a4* basal
- Afghanistan-centered microclades
- Iran–Pakistan foothill branches
Notes & context
G1a4 provides a bridge between early Iranian Plateau ancestry and later Indo-Iranian expansions into Afghanistan and Pakistan. It strengthens the atlas’s resolution of mid-Holocene population layers in eastern Iran.
References & external links