Helios deficiency affects BM megakaryocyte and lymphoid progenitor frequencies. (A–G) Relative abundance of the indicated BM populations in WT and KO mice at 6, 10, and 20 wk of age. Representative contour plots and statistical significance are shown. In the histograms of D and E, the control histogram shows the CD41 level of WT MPPs (CD48⁺CD150⁻ LSK). Numbers in the plots correspond to percentages. Each data point corresponds to one mouse; mean ± SD are shown per population for four to eight mice from multiple independent experiments. Unpaired two-tailed t test: *, P < 0.05; **, P < 0.01; ***, P < 0.001.