Stem cells: Blood lines from embryo to adult.

The article reports on a study providing a powerful evidence that yolk sac hematopoiesis does supply adult-forming cells as well. It is known that the yolk sac serves only the embryo, and that an independent origin of blood-forming stem cells begin in the region of the developing fetus known as the aorta-gonad-mesonephros (AGM). It was found that adult blood-forming cells in the AGM regions at least partly originated from Runx1-positive progenitors in the yolk sac.