Ifnar1 deletion leads to expansion of phenotypic committed myeloid and lymphoid progenitor populations in neonates and juveniles. (A-F) Absolute numbers of committed myeloid (A,B), megakaryocyte (C,D), lymphoid (E), and erythroid (F) progenitors in P0 liver or P14 bone marrow from mice of Ifnar1^+/− and Ifnar1^–/–-mice. For panels A and B, n = 13 to 21. For panels C-F, n = 4 to 7. For all panels, error bars reflect standard deviation. Surface marker phenotypes are specified in supplemental Table 2, and gating strategies are shown in supplemental Figure 2. ∗∗P < .01; ∗∗∗P < .001 using two-tailed t test.