In lethally irradiated recipients, only MPP display robust myeloid potential. Lethally irradiated recipient mice were transplanted with 5000 MPP (left column), 5000 CLP (middle column), or 5000 DN1 (right column) from GFP-transgenic mice. Recipient mice were also transplanted with 300 000 “helper” bone marrow cells, so that they would recover from the irradiation. Other than the irradiation dosage and the use of “helper” bone marrow, the description of this figure is identical to the description of Figure 3. (A) Bone marrow cells. (B) Splenocytes. (C) Thymocytes.