The present invention provides a molecular marker for the identification of pluripotent pre-mesenchymal, pre-hematopoietic stem cells. The invention further provides primitive progenitor cells identified by the molecular marker. Such cells have the potential to differentiate into both mesenchymal and hematopoietic phenotypes, as determined by a proliferative response to inductive growth factors and cytokines, and by their morphologic and cytochemical features.