English: Inferred ancestry of the main subclades within mtDNA haplogroup U8. The timescale (ka) is based on ML estimations for mitogenomes. Inset: Bayesian skyline plot of 34 Ashkenazi haplogroup K lineages, showing growth in effective population size (N_ef) over time. Haplogroup K arose within haplogroup U8~36 ka, in Europe or the Near East, with the minor subclades K1b, K1c and K2 all most likely arising in Europe, between the last glacial period and the Neolithic. K1a expanded from ~20 ka onwards, both in the Near East and Europe, with its major subclade, K1a1b1 mainly restricted to Europe (with a few instances in North Africa), arriving from the Near East by ~11.5 ka, the beginning of the Holocene. Almost half of mtDNAs in west/central European Ashkenazi Jews belong to haplogroup K, declining to ~15% in east European Jews, with almost all falling into three subclades: K1a1b1a, K1a9 and K2a2a1. These three founder clusters show a strong expansion signal beginning ~2.3 ka, with the overall effective population size for these lineages increasing 13-fold by 275 years ago.