The single-cell HSPC transcriptional landscape can be used to visualize HSPC populations and their relationships. (A) Diffusion map of all cells was colored on the basis of cell population using narrow gating. All populations were identified retrospectively by using the index sorting data. Populations were identified by using normalized index data. The cells of interest for each population are colored purple and enlarged for easier visibility. (B) Diffusion map of all cells with projection of data from recently published data sets. Data collected by Kowalczyk et al (C57BL/6, DBA/2) and Grover et al (Vwf-EGFP) is displayed. Both groups collected HSCs from mice 2 to 3 months (orange) and 20 to 25 months (blue) old. HSCs were defined as Lin^–c-Kit⁺Sca1⁺CD150⁺CD48^–.