Hierarchical structure of hematopoiesis depicting the stepwise differentiation from hematopoietic stem and precursor cells into effector cells of the main lineages. Shaded fields indicate Gfi1 and Gfi1b expression levels. CLP, common lymphoid progenitor; ETP, early thymic progenitor; GMP, granulocyte-monocyte progenitor; LMPP, lymphoid primed multipotent progenitor; MEP, megakaryocyte-erythroid progenitor; MPP, multipotent progenitor.