Haplogroup K

mtDNA (maternal line)

A branch of U8 that spread with the first Neolithic farmers. [isogg][aadr]

In the ancient British record

Frequency of K among ancient samples from Britain & Ireland, by period — from our aggregation of the CC0 Allen Ancient DNA Resource. See the full chart.

Bronze Age 15%
Early Medieval 9%
Iron Age 10%
Neolithic 31%
Roman 9%

Fuller account: K on Wikipedia.

Remember: a haplogroup is a deep, broad lineage shared by many people — not an ethnicity, a nationality or a clan. See what DNA can and can’t tell you.

Sources

[isogg] International Society of Genetic Genealogy (ISOGG), Y-DNA Haplogroup Tree. Reference — cite for haplogroup nomenclature only (not frequencies) · link
[aadr] Allen Ancient DNA Resource (AADR) v66, Mallick & Reich (Harvard), doi:10.7910/DVN/FFIDCW. CC0 1.0 (public domain dedication) · link