Using a recently characterized in vivo lineage tracing model, I have identified a novel fetal hematopoietic stem cell (HSC) that, although capable of supporting reconstitution of the blood system in an irradiated adult recipient, does not reside in the adult bone marrow in situ. This novel fetal HSC exhibits a differential lineage bias and gives…Continue Reading Flk2 Lineage Tracing Reveals a Novel, Developmentally-Restricted Hematopoietic Stem Cell