During embryonic development, several independent generations of hematopoietic cells
were identified. They occur in the yolk sac and the intra‐embryonic major arteries, in a …

Mammalian embryos produce several waves of hematopoietic cells before the
establishment of the hematopoietic stem cell (HSC) hierarchy. These early waves of …

We have traced emerging hematopoietic cells along human early ontogeny by culturing
embryonic tissue rudiments in the presence of stromal cells that promote myeloid and B cell …

Blood cells are continually produced from a pool of progenitors that derive from
hematopoietic stem cells (HSCs). In vertebrates, the hematopoietic system develops from …

Two distinct forms of erythropoiesis, primitive and definitive, are found in mammals.
Definitive erythroid precursors in the bone marrow mature in the physical context of …

The thymus produces new T cells throughout life but has no self-renewing ability and
requires replenishment and recruitment of progenitors derived from the bone marrow …

Highlights•During embryonic development, initial hematopoietic progenitors are generated
from hemogenic endothelium in multiple waves independently of hematopoietic stem cells …

Significant progress has been made towards a better understanding of the establishment of
hematopoiesis in the embryo. Hematopoietic precursors have been shown to arise …

The majority of T cells develop in the thymus. T-cell progenitors in the thymus do not self-
renew and so progenitor cells must be continuously imported from the blood into the thymus …

In utero, hematopoiesis takes place initially in the extraembryonic yolk sac, then switches to
the liver, thymus, and, finally, bone marrow. This chronologic sequence and the fact that all …