Decreases in megakaryocytic and myeloid progenitor numbers in Pten^+/-SHIP^-/- marrow. (A) Megakaryocyte progenitor cultures were fixed, dried, and stained after 10 days of incubation. The total number of colonies was assessed and expressed as values per femur. Cultures from SHIP^-/- marrow show decreased numbers of progenitors per femur, whereas the number of progenitors from Pten^+/-SHIP^-/- marrow was significantly reduced compared with all other genotypes. (B) BM cells were plated in duplicate in methylcellulose complete with growth factors, and the number and type of colonies was scored 10 to 12 days later. Pten^+/-SHIP^-/- mice showed decreases in GEMMs, BFU-Es, and total overall progenitor numbers compared with littermate controls. ^**P < .05 compared with wild-type and Pten^+/-alone; ^***P < .05 or less compared with all genotypes. Data were compiled from assays performed on 3 mice per genotype plus or minus the standard error of the mean (SEM) of the number of colonies.