Making Blood: The Haematopoietic Niche throughout Ontogeny

Figure 1

Timeline of haematopoiesis from early development to postnatal development in mice. This figure depicts the anatomical locations of haematopoiesis and the trafficking of haematopoietic stem cells (HSCs) and progenitor cells essential for maintaining haematopoiesis for life. Blood production begins at the mesoderm (blue, E6.0) and yolk sac (orange, all stages). From here, the first wave is initiated at the yolk sac blood islands (red, E7.0 and E8.5). Blood production is then shifted to the yolk sac and placenta (red, E9.5), with the latter providing blood to the foetus (pink) until birth. At E10.5, blood production initiates at the foetal liver and aorta-gonad-mesonephros (AGM) (red). The spleen initiates blood production at E14.0 (red) and continues to be a site of haematopoiesis after birth at time of stress. At E18.0, blood production shifts to the bone marrow (red), which remains the dominant site of haematopoiesis for life. After birth, adipocytes (yellow) begin to accumulate within the bone marrow and progressively increase as the mouse ages. Early development pictures modified from [17, 18].