Mapping human haematopoietic stem cells from haemogenic endothelium to birth

Human blood stem cells emerging from specialized endothelial cells in the wall of an embryonic aorta. UCLA scientists’ confirmation of this process clarifies a longstanding controversy about the stem cells’ cellular origin. | Credit: Hanna Mikkola Lab/UCLA, Katja Schenke-Layland Lab/University of Tübingen, Nature