| Haplogroup R-L21 | |
|---|---|
| Distribution of major subclade R-DF13 across western Europe | |
| Possible time of origin | 2,600 BC |
| Possible place of origin | South-west Britain |
| Ancestor | |
| Descendants |
|
| Highest frequencies | Irish Scottish Welsh Bretons English |
R-L21 or R1b1a2a1a2c, also known as R-M529 or R-S145, is a Human Y-chromosome DNA haplogroup. It is often linked to the Insular Celts. [1] One subclade, R-DF13 comprises over 99% of bearers. It is most frequently found among males in Ireland, but is also dominant in Scotland, Wales and Brittany, present in high frequencies in England and western France and present also to a lesser extent in Iberia, Scandinavia and the Low Countries. [2]
This haplogroup first emerges in the Early Bronze Age in Britain and Ireland, where the earliest samples begin to appear. Its introduction was part of a large genetic transformation associated with the Bell Beaker culture, wherein steppe descended peoples largely replaced Britain's earlier Neolithic population. The lineage reached a frequency of 90% in early Bronze Age Britain (being nearly absent in contemporary samples from the continent), it gradually declined through the Middle Bronze Age to 70% by the Iron Age (due to continental migrations which also increased the levels of EEF admixture among Britons). [note 1] It later fell to its modern levels in Britain after the Anglo-Saxon invasions. However, it still remains the dominant lineage in Ireland, Scotland, Brittany and Wales.
Below are listed some theorized lineages of prominent families.