Ontogeny of hematopoietic compartments in FL and blood. (A) Total numbers of viable nucleated blood cells in E12.5, E13.5, and E14.5 FLs. (B) Percentages of primitive RBCs, definitive RBCs, and platelets in E12.5, E13.5, and E14.5 fetal blood. (C) Percentages of LT-HSCs and 5 progenitor populations in E12.5, E13.5, and E14.5 FLs. (D) Total numbers of HSCs and 5 progenitor populations in E12.5, E13.5, and E14.5 FLs. E12.5 (n = 29), E13.5 (n = 31), and E14.5 (n = 38) C57BL/6J embryos were analyzed in 3 separate experiments, with data from 1 representative experiment shown. Viable cells were determined by Trypan Blue exclusion.