Figure 1: Source of blood cells during gestation through after birth. Intraembryonic yolk sac is the first site of blood cells observation at around E7.0–E7.5. The de novo hematopoiesis in the placenta and AGM occurs at nearly similar wave of gestation (around E8.5–E10.5) beforeit circulates into fetal liver where there is the large HSC pool during gestation. At around E16.5, the HSCs migrate and reside within the bone marrow which finally becomes the source of HSC in adult life (adapted from [10]).