Reduced numbers of primitive hematopoietic cells within GATA-2^+/– bone marrow. Bone marrow nucleated cells from each genotype were assessed for CAFC ability using limiting dilution long-term culture assays. Five to 6 dilutions were employed for each genotype in individual experiments. The absolute number of CAFCs per harvest was measured at week 2 (A) (P = .019, n = 5), week 3 (B) (P = .001, n = 6), and week 5 (C) (P = .001, n = 6). Horizontal bars depict the mean of cumulative data. GATA-2^+/– bone marrow displays a decrease in Lin^–c-kit⁺Sca-1⁺CD34^– hematopoietic stem-cells. Using flow cytometry, a 2-fold reduction of LKSCD34^– cells in GATA-2^+/– marrow compared with wild-type marrow is evident in the single experiment shown here (D). Numbers in R3 gates indicate % of LKS34^– cells in marrow. The cumulative data of multiple independent experiments are depicted in panel E (P < .001, n = 8). To enumerate the size of the GATA-2^+/– functional stem-cell pool in Lin^–c-kit⁺Sca-1⁺ or Lin^–c-kit⁺Sca-1⁺CD34^– cells, each primitive cell population was sorted and cultured in limiting dilution long-term culture assays and CAFCs were scored at week 5. The cumulative data of multiple experiments are depicted in panel F (LKS: P = .003, n = 7; LKSCD34^–: P = .005, n = 7). Error bars indicate the standard error of the mean. Statistical analysis was performed using the Student t test.