Complementation of Fanca^−/− fibroblasts with FANCA rescues the reprogramming efficiency. (A) Percentage of senescent cells 4 days after reprogramming under hypoxic conditions (5% O₂). (B) Frequency of iPSC colonies 16 days after reprogramming (5% O₂). (C) Alkaline phosphatase–positive iPSC colonies on representative 10-cm tissue-culture dishes 16 days after reprogramming. (D) Percent contribution of CD45.1⁺Fanca^−/− iPSC-derived cells to day 14.5 embryonic fetal liver hematopoietic cells. Shown is the percentage CD45.1⁺Fanca^−/− cells of all CD45⁺ hematopoietic cells as ascertained by flow cytometry analysis of individual fetal livers. Filled circles, WT; open circles, Fanca^−/− + GFP; gray circles, Fanca^−/− + FANCA. Each symbol represents an individual animal. Horizontal lines represent the median. **P < .01; *P < .05; NS indicates not significant by Wilcoxon rank-sum test.