M269 marks the most common haplogroup found in Europe. Its frequency exceeds 80% in parts of western Europe and it occurs at lower frequencies in central and eastern Europe. It marks an ancient migration into Europe prior to the LGM and is believed to have survived in refugia in Iberia, the Balkans and possibly elsewhere before expanding northwards again. It apparently comprises two major branches defined by DYS1/p49a,f haplotypes 15 and 35, but this branching cannot yet be included in the tree because the underlying mutation is not verified as a unique event polymorphism.

http://www.isogg.org/tree/M269.html