Donor chimerism of mice that received a transplant of transduced test cells in competitive repopulation assays. Peripheral blood donor chimerism was determined by flow cytometry after staining with antibodies against CD45.1 and CD45.2. (A) Donor chimerism of individual mice in the first cohort over a time period of 12 months. The mean donor chimerism of mice that received a transplant of mock-transduced Fancc^−/− control cells was significantly lower than that of mock-transduced WT control or MD9-FANCC/EGFP–transduced Fancc^−/− cells (*P < .05). (B) Peripheral blood cell chimerism of recipient in secondary transplants receiving transduced cells from the second cohort 6 months after the initial transplantation. (C,D) Analysis of genotype and transduction efficiency of myeloid progenitors. CD45.2⁺ BM cells were sorted and cultured in semisolid medium to grow myeloid progenitors. DNA from individual colonies was isolated and amplified to detect the genotype (C) and presence of the provirus (D). Representative gels of the amplified PCR products are shown. The test cell genotype and the provirus used are indicated.