Etv6^R355X/+ mice generate all HSPC populations. (A) Representative gating strategy to identify HSPC subpopulations within LSK cells, including long-term HSCs (LT-HSCs), short-term HSCs (ST-HSCs), MPP2, MPP3, and MPP4, showing representative plots from Etv6^+/+ mouse BM (top row) and Etv6^R355X/+ BM (bottom row). (B) Schematic diagram describing the hierarchical relationship between the earliest HSPC subpopulations. (C) Overall BM cellularity from both femurs of Etv6^+/+ (green, n = 9) and Etv6^R355X/+ (red, n = 9) mice. (D) Frequency (top) and absolute number (bottom) of LSK cells (left) and HSPC subpopulations (right) from Etv6^+/+ (green, n = 9) and Etv6^R355X/+ (red, n = 9) mice at 3 months of age. Data are representative of 4 independent experiments and show mean ± SD. (E) Frequency (top) and absolute number (bottom) of committed progenitor populations in Etv6^+/+ (green, n = 9) and Etv6^R355X/+ (red, n = 9) mice at 3 months of age. Data are representative of 2 independent experiments and show mean ± SD. ∗P < .05; ∗∗P < .001; and ∗∗∗P < .0001 were determined by unpaired t tests or two-way ANOVA with a Holm-Šidák multiple comparisons test. CLP, common lymphoid progenitor; CMP, common myeloid progenitor; GMP, granulocyte-monocyte progenitor; MEP, megakaryocyte-erythroid progenitor.