The hematopoietic hierarchy. The figure depicts selected cell surface determinants used to isolate PHSCs. Common myeloid progenitors (CMPs) and common lymphoid progenitors (CLPs) can also be defined in the mouse. The figure shows that only PHSCs provide long-term, stable repopulation of recipients, while other cells mediate different degrees of transient reconstitution. The radioprotective megakaryocyte/erythroid progenitor in the mouse is indicated.