All BM colonies harbored the JAK2V617F/Vav-Cre recombination confirming previous data that transplanting at least 30 LT-HSCs is necessary to fully develop an MPN phenotype in a mouse model and respectively 100% (Fig. 3E left), 94% (Fig. 3E middle), and 47% (Fig. 3E right) were inactivated for Trp53, illustrating the competitive advantage of JAK2V617F/Vav-Cre/Trp53−/− over JAK2V617F cells. This evidence concerns the gene VAV1 and myeloproliferative disorder.