Fig. 4. Identification of myeloid progenitors present in the different CD34 and CD41 populations purified from EB6, yolk sac, aorta-gonad-mesonephros (AGM), fetal liver and bone marrow cells. The initial population (unfractionated) was subdivided into CD34⁺CD41⁺, CD34⁺CD41^– and CD34^–CD41⁺ cell populations for EB6, yolk sac (YS), fetal liver (FL) and bone marrow (BM) cells. AGM cells, were subdivided into the entire CD41⁺, the CD34⁺CD41^– and CD34^–CD41^– cell fractions. Myeloid colony formation from each population was studied in methylcellulose. Results are expressed as a distribution (expressed in percentage) of various myeloid colonies including mixed colonies in each population.