A diagrammatic presentation of the roles of zidh1/2 and IDH1-R132H mutation in primitive myelopoiesis and definitive hematopoiesis during zebrafish embryonic development. zidh1 and zidh2 played redundant roles in regulating myeloid differentiation, whereas zidh1 but not zidh2 also played a role in the maintenance of definitive hematopoiesis. Human IDH1-R132H and zebrafish idh1-R146H resulted in an increased 2-HG that induced expansion of primitive myelopoiesis.