The Relationship Between Cell Lineage and Differentiation in the Early Mouse Embryo

The notion that particular types of terminally differentiated cells originate from specific ancestral cells during ontogeny is one of wide currency and long standing. It arose principally from studies on lower chordate and invertebrate embryos carried out in the latter part of the last century and the beginning of the present one (see Davidson, 1976, for a recent review). The concept of stem cells, which may persist into adulthood in a variety of tissues, is clearly related to that of specific cell lineages (Cairnie et al., 1976). Thus neural crest cells, haematocytoblasts, and neuroblasts are believed to give rise to distinct constellations of specific mature cell types.