In vitro differentiation potential of CD34⁺c-kit⁺ cells from day 11 AGM and fetal liver. (A) FACSorting of CD34-FITC/c-kit-PE staining of day 11 fetal liver and AGM cells. Sorting gates were set using isotype-specific control antibodies, and dead cells were excluded using propidium iodide staining. The percentage of double-positive cells is 2.1% (fetal liver) and 0.1% (AGM). (B) Summary of the 2-step culture assay to test the differentiation potential of single CD34⁺/c-kit⁺ cells. (C) Photomicrograph of clone 1G12 after 13 days in culture under “multipotent conditions.” (D) Photomicrograph of clone 1G12 after 13 days of culture under lymphoid differentiation conditions. (E) Photomicrograph of clone 1G12 cultured for 13 days under myeloid conditions. (F) FACSscan analysis of the cells in panel D using anti-B220 and anti-IgM antibodies. (G) May-Grünwald-Giemsa staining of the cells in panel E; note the multimyeloid nature of the clone. The open arrowhead indicates a megakaryocyte; filled arrowheads indicate macrophages; arrows indicate myeloid cells of the granulocytic series; and the bar indicates a cluster of basophilic myeloid cells.