IFN-γ treatment of Fanca^–/– recipients is sufficient to allow long-term engraftment of syngeneic WT bone marrow cells. Six months following transplantation with CD45.1⁺ WT donor BM nucleated cells, selected recipients from a second cohort of (A) Fanca^–/– or (B) Fancg^–/– mice received transplants from secondary recipients to verify that the engrafting CD45.1 donor cells were long-term repopulating stem cells. The CD45.1⁺ chimerism of each primary recipient (left panels) and the chimerism of 3 secondary recipients (right panels) from each respective primary recipient are indicated. Bars represent the mean CD45.1⁺ chimerism. *P < .001 comparing chimerism of Fanca^–/– and Fancg^–/– recipients treated with IFN-γ versus vehicle-treated Fanca^–/– and Fancg^–/– recipients.