Identification of new subpopulations of prePB and PB stages. (A) Seurat k-nearest neighbors clustering identified 5 clusters, including 4 clusters for prePB and 1 cluster for PB. (B) Violin plots representing the expression of top marker genes identified using the pseudotime analysis for each cluster. (C) Number of positive differentially expressed genes identified in the 5 clusters using pairwise comparisons (one cluster vs all other cells). (D) The heat map showed the top 50 genes upregulated in each cluster. Keys genes coding TFs, EEs, ligands, and receptors were indicated and colored in gray, red, green, and blue, respectively. (E) Expression levels of TFs identified in panel D. High and low expression were represented in dark blue and in yellow, respectively. (F) Gene set enrichment analysis of the whole genes upregulated in each cluster.