Hematopoiesis is the formation of all blood lineages, including
myeloid and lymphoind cells. The process starts from a
hematopoietic stem cells (HSCs). HSCs are multipotential stem cells
which reside mostly in fetal liver in fetus and in the bone marrow
in adult animal. Based on their potential to differentiate to
sublineages, HSCs can be further defined as short-term and
long-term stem cells.