Distributions of myeloid/erythroid colony types in HOXA9−/− and normal marrow are similar. In 6 separate experiments, well-separated individual colonies were plucked from cultures of (□) HOXA9−/− (n = 166) and (▪) normal C57 (n = 164) marrow after 7 to 10 days of incubation. Cytospin preparations were stained and scored as 1 of 5 colony types. All colony types were represented in HOXA9−/− marrow in virtually the same percentage as in normal marrow, except for a small reduction in the percentage of pure granulocyte colonies and an increased proportion of mixed erythroid/myeloid colonies.