Considering the fact that ET patients had low JAK2 V617F allele burden while PV patients had high mutant allele burden, we postulate that when the mutant allele burden was low, megakaryopoiesis was enhanced with the increase of mutant allele burden, but erythropoiesis was weak, not increased with mutant allele burden, and when the mutant allele burden was high, the phenomenon reversed. Here, JAK2 is linked to essential thrombocythemia.