E-protein activity regulates the balance between myeloid- and lymphoid-lineage specification at the LMPP stage. The developmental scheme of hematopoiesis is drawn according to Adolfsson et al.⁶  The stage at which the balance of E proteins (E) and Id proteins is thought to play a role in myeloid-versus-lymphoid decisions is shown with a rectangle. Cells expressing high levels of Id1 are shown in filled circles.