(A) Schematic representation of the murine Dnmt3a locus, targeting vector, targeted Dnmt3a locus (LSL allele), and targeted Dnmt3a locus after Cre recombinase-mediated excision of the LSL cassette (knockin allele). (B) DNA of heterozygous mice carrying the targeted Dnmt3a locus was analyzed by PCR (primer: Loxp-tF/Loxp-tR) and sequencing (primer: ZMK-2F4/Zeo-tR). Mutant Dnmt3a of cDNA was detected in the BM cells of Dnmt3aR878H/WT mice (D3A-22-F/D3A-UTR-R). (C) Statistical analysis of hemoglobin levels and cell counts in the PB. (D) Morphological comparison of PB smears between mice. (E–G) Flow cytometric analyses of mature hematopoietic cell populations among PB (E), total nucleated BM (F), and splenic cells (G). (H and I) Flow cytometric quantification of mature hematopoietic cell populations and the indicated HSPC populations among SP cells of mice. Mean ± SEM values are shown. *P < 0.05, ***P < 0.001.