Haplogroup R-L21
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. One subclade, R-DF13 comprises over 99% of bearers. It is dominant among males in Ireland, 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.