A complex linkage in the developmental pathway of endothelial and hematopoietic cells

During normal vertebrate development, hematopoietic and endothelial cells f orm closely situated and interacting populations. Although the close proxim ity of cells to each other does not necessarily mean that they are relative s, accumulating evidence indicates that hematopoietic and endothelial cells are indeed close kin; they share common progenitors and each is able to be come the other under certain circumstances. This article summarizes recent advances in the developmental relationship between hematopoietic and endoth elial cells.