Loss of Casp9 or Apaf1 leads to dysplastic hematopoiesis and reduced survival after transplantation. (A) FLCs from Casp9^+/+ or Casp9^−/− pups were transplanted into lethally-irradiated WT C57BL/6J recipients. Recipients of Casp9^−/− FLCs had significantly decreased survival compared with mice transplanted with Casp9^+/+ FLCs. (B) Similarly, recipients of Apaf1^−/− FLCs had significantly reduced survival compared with mice transplanted with Apaf1^+/+ FLCs. (C) Examination of bone marrow in moribund Casp9^−/− or Apaf1^−/− transplant recipients revealed signs of erythroid dysplasia (arrows = nuclear blebbing), and features of abnormal myeloid differentiation, including hyperlobulated neutrophils and a shift to less differentiated forms (D). (E) The proportion of cells showing dysplastic changes in the erythroid and myeloid lineages was increased in recipients of Casp9^−/− or Apaf1^−/− FLCs. *P < .05, **P < .005, ***P < .0005.