haplogroups.info
Y-DNA Haplogroup Atlas

A · BT · CT · CF · F · I · I2 · I2a · I2a1 · I2a1b · I2a1b-S17250

Haplogroup I2a1b-S17250

I2-S17250 Dinaric Upper Branch

Macro-haplogroup
I
Parent clade
I2a1b
Formed (estimate)
c. 2,600–3,200 years before present
TMRCA (estimate)
c. 1,700–2,100 years ago

Overview

I2a1b-S17250 is one of the most important branches of the I2a1b (M423 > Y3120) radiation. It formed in the Carpathian and western Balkan region during the late Iron Age and represents a major paternal lineage among early South Slavic and Dinaric populations. Its demographic pattern shows strong founder expansion, paralleling the early medieval Slavic dispersals.

Geographic distribution

Highest frequencies occur in Bosnia, Croatia, Serbia, Montenegro and western Bulgaria. Strong representation is also found in Slovenia, Romania, Moldova and western Ukraine. Minor presence extends into Greece and Hungary. Diaspora communities in the Americas show notable levels due to recent Balkan migrations.

Ancient DNA

  • Medieval burials from the western Balkans contain lineages closely related to S17250, matching its demographic expansion during South Slavic formation.
  • Iron Age individuals from the Carpathian Basin show upstream CTS10228–Y3120 variation ancestral to the S17250 clade.
  • Byzantine-era individuals from the Balkans and northern Anatolia include paternal lines clustering near S17250-related branches.

Phylogeny & subclades

Positioned directly under I2-Y3120, S17250 is a major downstream node that gave rise to large subbranches such as PH908 and Y18331. Defining SNPs are S17250, A8613 and Y4460. Its structure displays clear regional grouping between western Balkan and Carpathian populations.

  • I2-PH908
  • I2-Y18331
  • I2-S17250* basal lineages

Notes & context

S17250 forms a crucial backbone for reconstructing the demographic expansion of South Slavic populations and is heavily represented in Balkan genetic genealogy projects.