SHIP^–/– HSCs exhibit decreased apoptotic rate. (A) Representative FACS plots of DAPI versus Annexin V after gating on KTLSFlk2^– cells. Bar graph shows the percentage of KTLSFlk2^– that are apoptotic based on the Annexin V⁺ and DAPI^– staining: SHIP^–/– (▪); WT (▦). (B) Representative FACS plots for TUNEL staining after gating on KTLS cells. Bar graph represents the percentage of KTLS cells positive for TUNEL staining: SHIP^–/– (▪); WT (▦). Significance was established using the unpaired student t test (Prism 4): *P < .01; ⁺⁺P < .005 (mean ± SEM; n ≥ 3).