Single-cell transcriptomics in ME-1 cells reveals branching heterogeneity consistent with GATA2 regulation. (A) Cumulative expression distributions for heptad genes in single ME-1 cells. cppt: counts per 10 000 reads. (B) Pairwise Spearman correlations between heptad genes in single cells. (C) Censored distributions of gene expression for the gene pairs highlighted in panel B. The 2 bottom panels show the expression of the second gene in the lowest 10% and highest 5% of expressing cells for the first gene. P values refer to a Kolmogorov-Smirnov 2-sample test between the purple and green distributions. (D) Uniform manifold approximation and projection (UMAP) embedding of ME-1 cells and cell state assignment based on Northstar⁵⁵ and the Palantir data, used as an atlas (Figure 1). Streamlines show RNA velocity as computed by scVelo,⁵⁷ projected onto the same embedding. Inset: the branching phenotype within ME-1 cells, indicating that the cell flux into the ery-precursor–like state is a rare event. (E) Expression of the 4 heptad genes highlighted in panel B on the embedded cells. (F) Fold increase in heptad gene expression across the HSC to ery-precursor–like state in ME-1 cells (left). Fold increase in heptad gene expression across the HSC-to-ery-precursor state in normal CD34⁺ HSPCs cells (right). (G) Performance of random forest classifiers between HSC-like and ery-precursor–like states in ME-1 cells, trained solely on Palantir data with a spectrum of selected features. The presence of GATA2 expression in the model is essential for its accuracy. Error bars indicate standard deviation over 10 runs of the predictor with data resampling in each run.