Violin plots showing that DYRK1A is overexpressed in chr. 21amp HSPCs compared with non-chr. 21amp control cells including myelofibrosis (MF, n = 2,056 cells from eight MF donors), pre-leukemic stem cells (preLSC, n = 1,107 nonmutant phenotypic HSCs, identified in 12 BP-MPN donors), TP53 -mutant-non-chr. 21amp BP-MPN (no chr. 21amp m TP53 , n = 6,629 cells from 14 BP-MPN donors) and WT cells ( n = 5,002 from nine healthy donors). Each dot represents the expression value (log 2 -normalized UMI count) for a single HSPC, with median and quartiles shown in white. Expressing cell frequencies are shown on the bottom of each violin plot for each group.