Overview
I1-BY351 is a coastal North Sea branch of haplogroup I1, with roots in the maritime societies of the late Nordic Bronze Age and subsequent Iron Age Frisian, Saxon and North Sea Germanic communities. Its formation period aligns with the consolidation of cultural groups along the Frisian coast and Jutland, where seafaring, trade and trans-regional communication networks shaped demographic patterns. BY351 displays a demographic signature associated with moderate expansions characteristic of small but influential coastal populations.
Geographic distribution
Modern carriers are most frequent along the North Sea littoral: the Netherlands (Frisian region), northern Germany, Denmark and coastal England. Lower frequencies occur in Belgium, Normandy and Norway. Its appearance in England reflects Anglo-Saxon and Frisian settlement events.
Ancient DNA
- Iron Age burials in Frisia and Lower Saxony show paternal lineages close to the basal Z58 > BY351 cluster.
- Anglo-Saxon era cemeteries in England contain individuals clustering near early BY351 microclades.
- Viking Age burials along the North Sea occasionally fall within or adjacent to the BY351 phylogenetic zone.
Phylogeny & subclades
I1-BY351 is a minor yet distinct branch within the Z58 > Z138 coastal radiation. BY351, Y51842 and BY354 define the clade. Internal structure is limited but regionally patterned, reflecting ties to North Sea coastal cultures.
- I1-Y51842
- I1-BY354
- Basal BY351*
Notes & context
I1-BY351 provides useful insights into West Germanic and Frisian demographic history. Its distribution mirrors coastal trade and migration corridors from the late Bronze Age through the early medieval period.
References & external links