Fancc^–/– hematopoietic stem/progenitor cells are less quiescent than WT control cells. (A) A representative experiment demonstrating the gating method used for in vivo and in vitro BrdU pulse assays of SCL cells. Either mice or lin^– cells harvested from Fancc^–/– and WT mice were pulsed with BrdU and analyzed for simultaneous detection of Sca1, ckit, and BrdU incorporation as described in “Study design.” (B) Mean BrdU incorporation in SCL cells. Data shown are the mean of 5 experiments for both in vitro and in vivo pulsing methods, *P < .05. (C) Cell cycle analysis of a representative experiment. Lin^– cells from Fancc^–/–,WT, and p21^{cip1/waf1–/–} mice were stained with Hoechst 33342 and Pyronin Y. WT and p21^{cip1/waf1–/–} samples were used as controls to set fluorescent cytometer parameters. Data shown are one of 5 representative experiments with similar results. (D) Mean %G0 lin^– cells. The mean of 5 independent experiments is shown, **P < .002. A Student t distribution and P values were determined using GraphPad Prism 3.0a software (San Diego, CA).