Flow cytometric analysis of BM and spleen after transplantation with BM transduced with either Jak2V617F or Jak2wt in Balb/c mice. Dot plots demonstrate an approximately 10-fold increase in the ter119⁺ and the CD71⁺/ter119⁺ population in the spleens of Jak2V617F compared with Jak2wt animals. Most CD71⁺/ter119⁺ cells represented a more immature erythroid population at the level of BFU-Es. Representative plots from 1 of 12 independent experiments for the mutant mice and 1 of 10 experiments for the Jak2wt mice are shown. In the BM of Jak2V617F mice, a prominent population of mature Gr1⁺/Mac1⁺ myeloid cells was detectable that had increased approximately 3-fold compared with the BM of Jak2wt mice and approximately 10-fold in spleens of Jak2V617F compared with spleens of Jak2wt mice. B220⁺ B cells were proportionately decreased in the BM and spleens of Jak2V617F mice compared with Jak2wt mice.