Wild-type and Gab2^−/− BM have the same absolute number of primitive hematopoietic stem/progenitor cells. (A) BM cells were blocked with normal mouse serum; stained with lineage antibody cocktails, including Gr-1, Mac-1, B220, Ter119, CD4, and CD8; and combined with combinations of Sca-1, c-Kit, Flk2 (flt3), CD34, and additional markers as described in “Materials and methods.” Shown are representative profiles for lineage-negative BM cells analyzed for the indicated sets of markers defining short-term HSC/multipotent progenitor (ST-HSC/MPP) cells, long-term HSCs (LT-HSCs), granulocyte-macrophage progenitor (GMP) cells, megakaryocyte-erythroid progenitor (MEP) cells, and the common myeloid progenitor (CMP) and common lymphoid progenitor (CLP) cells. The values in the wild-type and Gab2^−/− panels represent the percentage of the total nucleated cells staining with the associated markers. (B) A total of 6 independent wild-type and 6 independent Gab2^−/− mice were used to analyze the populations described above. The values represent the number of cells per 10⁶ viable adult BM cells obtained from 2 tibias and 2 femurs per mouse. The plotted values represent the average numbers of the 6 mice per group and the standard deviation. Error bars represent the mean plus or minus a standard deviation.