Apc haploinsufficiency affects the repopulating capacity of HSCs in vivo. (A) Mice with chimeric BM were generated by transplanting an equal number of wild-type CD45.1⁺CD45.2⁺ (CD45 heterozygous) BM cells and CD45.2⁺ (homozygous) BM cells from Mx1-Cre⁺Apc^fl/+ or Mx1-Cre⁻Apc^fl/+ mice 4 weeks after pI-pC induction of the Apc deletion. (B) Flow cytometric analysis of CD45.1- and CD45.2-stained PB cells from representative chimeric Mx1-Cre⁺Apc^fl/+ or Mx1-Cre⁻Apc^fl/+ mice 1 month after transplantation. The numbers indicate the percentage of cells in each population. (C) Histogram showing the relative ratio of CD45.2⁺ versus CD45.1⁺/CD45.2⁺-stained PB cells in Mx1-Cre⁻Apc^fl/+ versus Mx1-Cre⁺Apc^fl/+ chimeric mice examined at 1 to 4 months after transplantation (mean ± SD of 8-10 animals). *P < .05; **P < .01.