Morphology of dysplastic mixed-like hematopoietic colonies in the AML1/EVI1^/+ fetal liver culture. On days 7 and 10 of culture, cytocentrifuge preparations of cells from mixed-like colonies were stained with Wright-Giemsa for morphologic examination (OL, 100 ×/1.40; OM, × 1000), benzidine for the presence of erythroblasts (OL, 10 ×/0.30; OM, × 100), or choline esterase for the presence of megakaryocytes (OL, 60 ×/1.40; OM, × 600). AML1/EVI1/⁺ mixed-like colonies in the bottom panels show retarded maturation and hypogranulation of myeloid cells as well as the absence of erythroid cells. In contrast, WT mixed colonies in the top panels show normal trilineage differentiation.