Palld^−/−fetal liver hematopoietic stem cells (HSCs) have the ability to reconstitute the hematopoiesis of lethally irradiated mice. (A) Equal numbers of wt or Palld^−/− fetal liver cells were injected into lethally rradiated recipient mice, and the survival ratio of recipient mice was measured for 6 weeks. Nine mice received wt fetal liver cells, and 6 mice received Palld^−/− fetal liver cells. (B) Genotyping of peripheral blood (PB), bone marrow (BM), and spleen (SP) of recipient mice 2 months after reconstitution shows the dominance of fetal liver–derived cells in the hematopoietic organs of Palld^−/− HSC-reconstituted mice. W1 to W3 indicate the recipient mice receiving transplants with wt fetal liver cells; R1 to R5, the recipients of Palld^−/− fetal liver cells. (C,D) Proportion of Mac-1⁺ Gr-1⁺ (C) and Ter119⁺ (D) cells among all nucleated peripheral blood cells (PB), bone marrow cells (BM), or spleen cells (SP) in wt and Palld^−/− fetal liver cells reconstituted mice. No significant difference was observed between wt and Palld^−/− fetal liver cells reconstituted mice. Error bar represents plus and minus a SD.