Overview
Haplogroup I3f (Y18500) is a rare Upper Paleolithic branch of the I3 lineage that appears to have developed among highland West Eurasian populations occupying the transition zone between eastern Anatolia, the northern Levant and northern Mesopotamia. Its deep time depth places its origin in the period surrounding the Last Glacial Maximum, when populations in the Near East were fragmented into multiple semi isolated refugia. I3f represents one of the paternal lines that successfully persisted through this climatic bottleneck and later contributed to the complex mosaic of early Holocene foragers and pre Neolithic communities.
Geographic distribution
Modern carriers of I3f are sparsely distributed, with most occurrences reported from southeastern Turkey, northern Syria, northern Iraq and northern Iran. Occasional examples in Armenia and the Caucasus foothills suggest ancient links between highland and lowland refugia. Very low level presence in parts of the eastern Mediterranean and Anatolian diaspora populations likely reflects historical era dispersals rather than independent centers of origin.
Ancient DNA
- Upper Paleolithic and Epipaleolithic genomic clusters from the Levant and northern Mesopotamia show paternal diversity patterns compatible with early I3 branches, including the expected time depth of I3f.
- Pre Pottery Neolithic individuals from sites in the northern Fertile Crescent carry Y chromosome lineages that sit near the base of the I and J radiations, and some are genetically close to the ancestral position of I3 subclades.
- Later Neolithic and Chalcolithic remains from eastern Anatolia and northern Mesopotamia preserve a mixture of incoming farmer lineages and older highland derived substrata, within which deep I3 lineages such as I3f would have persisted at low frequencies.
Phylogeny & subclades
Within haplogroup I3, I3f branches alongside I3a, I3b, I3c and I3d as part of a set of very old but sparsely represented lineages. Y18500 and its associated SNPs define a distinct cluster that has not undergone major secondary radiations, which is typical of lineages that persisted in geographically restricted populations. Its position in the tree helps anchor the early diversification of I3 and provides additional calibration points for dating the emergence of West Eurasian specific Y haplogroups.
- I3-Y18504
- I3-FGC5650
- Basal I3f* highland Near Eastern lineages
Notes & context
I3f is valuable for understanding the deep time structure of Near Eastern male lineages because it marks a surviving branch from a period when the region was home to multiple distinct refugial populations. The clade highlights the role of rugged landscapes and fragmented habitats in preserving older genetic diversity that was later overlain, but not entirely replaced, by Neolithic and Bronze Age demographic expansions.
References & external links