Frequency of mutations in LTC-IC–derived colony-forming cells. (A) Tracking of mutations in individual CFCs derived from LTC-ICs. (Upper) Proportion of LTC-ICs according to mutation burden. (Lower) Representation of the genotypes of LTC-IC–derived CFCs to 10 colonies. Each column represents 1 CFC. Colored boxes represent mutated CFCs; open boxes represent nonmutated CFCs. Each line represents 1 mutation. Number of colonies analyzed per sample is indicated. Bold type indicates major mutations. (B) Proportion of mutated cells in the BM MNC, the CD34⁺CD38⁻ HSPC, and LTC-IC–derived CFCs according to variant category. Percentages of mutated cells in bulk BM MNC (BM) represent twice the VAF of heterozygous mutations on autosomes or onefold the VAF of homozygous autosomal mutations or homozygous mutations of X chromosome genes in male subjects. Percentages of mutated cells in the CD34⁺CD38⁻ compartment and LTC-IC–derived CFCs represent the proportion of mutated colonies among all analyzed colonies. The numbers and type of mutations are indicated for each category. Results are expressed as means ± standard error of the mean (SEM) and compared with Student t test.