MK-HSCs can directly differentiate to MK within 1 cell division. (A) 60-well Terasaki plate sorted with single cells of CD41⁺HSC, CD41⁻HSCs from Runx1^–/–and Runx1^F/F mice after a 2-day culture in Stemspan medium containing SCF and TPO. (B) Kinetics of the plated single cell divisions. The x-axis indicates the hours after plating the cells post sorting. y-axis indicates the percentage of divided cells in total plated cells. (C) Representative images of the divided large MK-like and small non-MK–like daughter cells. (D) Quantification of the cultured cells as single large MK-like cells, single small non-MK-like cells, double large MK-like cells, and double small non-MK–like cells. (E) Heatmap of key platelet or MK-related gene expressions in large MK-like cells and small non-MK–like cells for Runx1^–/–group. (F) Heatmap of key platelet/MK-related gene expressions in large MK-like cells and small non-MK–like cells for Runx1^–/–group. ∗∗P < .01 and ∗P < .05.