Nontransplanted SETD1A-deficient HSCs are defective. (A) Plot depicts mean fluorescence intensities (MFI) of Kit expression on LT-HSCs. (B) Plot shows the dilution of H2B-mCherry in LT-HSCs 8 weeks after doxycycline-mediated labeling of LT-HSCs in SCL-CreER^T+;Setd1a^F/F;R.26-rtTA^ki/ki;Col1a1-tetO-H2B-mCherry^ki/ki or control mice. (C) Quantification of H2B-mCherry dilution as is shown in panel B. Data from 2 independent experiments are shown. (D) Frequencies of SCL-CreER^T+;Setd1a^F/F or SCL-CreER^T+;Setd1a^+/+ LT-HSCs (left) and ST-HSCs (right) in G₀ (Ki-67⁻ DAPI⁻), G₁ (Ki-67⁺ DAPI⁻), or S/G₂/M (DAPI⁺) phases of the cell cycle. Data from 2 independent experiments using n = 9 (+/+) and n = 10 (F/F) mice, 8 and 9 days after last TAM treatment are shown. (E) Histogram of DAPI-stained LT-HSCs. (F) Frequency of LT-HSCs and ST-HSCs containing fragmented DNA (sub-G1) was determined, as is shown in panel E. Data from 2 experiments using n = 9 (+/+) and n = 10 (F/F) mice were pooled. (G) Frequencies of annexin V⁺ cells in LT-HSCs and ST-HSCs in vivo. Data from 2 independent experiments are shown. (H) Graphs show the MFI for phosphorylated histone 2A.X at Ser139 (γH2A.X) in LT-HSCs and ST-HSCs in vivo. Data from 3 independent experiments are shown. (I) MFI of Cell Rox Deep Red to detect ROS levels in LT-HSCs and ST-HSCs in vivo. Data from 2 independent experiments are shown.