Subclade L2a1a is defined by substitutions at 3918, 5285, 15244, and 15629. There are two L2a clusters that are well represented in southeastern Africans, L2a1a and L2a1b, both defined by transitions at quite stable HVS-I positions. Both of these appear to have an origin in West Africa or North West Africa (as indicated by the distribution of matching or neighboring types), and to have undergone dramatic expansion either in South East Africa or in a population ancestral to present-day Southeastern Africans.