HSCs isolated from Osx-Rac^del mice have normal function. (A) Osx-Rac^del donor BM transplantation is able to sustain normal blood counts in lethally irradiated recipient mice (white blood cell count [WCC], 19.1 ± 7.9 × 10³/μL; hematocrit [HCT], 47.6% ± 4.6%; platelet count, 616 ± 238 × 10³/μL). n = 10 recipient mice. (B) Normal blood counts in lethally irradiated secondary recipient mice (WCC, 9.1 ± 2.0 × 10³/μL; HCT, 46.6 ± 3.9%; platelet count, 880 ± 130 × 10³/μL). (C) Similar BM competitive repopulation between Osx-Rac^del and Cre⁻ controls (donor chimerism, 37.4% ± 3.4% vs 35.1% ± 8.6% 16-week chimerism, P = ns; n = 6-7 recipients per condition). (D) Donor chimerism over time of BM derived from Osx-Rac^del and Cre⁻ controls (P = ns all time points). All values are means ± SD.