Fig. 1: Long-term repopulating cells are detected in FBM at E15.5.

a FBM primary and secondary transplant. b PB reconstitution in FBM primary recipients (n = 9–18). c Lineage output in individual primary recipients 20 weeks post-transplant (n = 8–19); myeloid bias (%myeloid > %B cell), red asterisk; b-lymphoid bias (%B cell >70%), blue asterisk. d %CD45.2+ PB in secondary recipients of FBM. Data are means ± SE of three independent transplants (n = 5/transplant, Mann–Whitney test, two-tailed). 1o, primary; 2o, secondary; BM bone marrow, FBM fetal BM; NS not significant. Source data are provided in the Source Data File. See also Supplementary Fig. 1.