THE ORIGIN AND MIGRATION OF PRIMORDIAL GERM-CELLS IN THE MOUSE

Primordial germ cells (PGCs) are the founders of the gametes. They mig rate from their origin to combine with the somatic component of the go nad. Progenitors in mice have been recognized in the proximal epiblast . When and how these cells are allocated to the germ line has not been elucidated fully. Numerous growth factors have been described which a ffect PGC survival, proliferation and directional control during their migration. The extracellular matrix also may play a role in PGC migra tion, particularly fibronectin and laminin. Once they have arrived at the gonad, PGCs aggregate with one another. The molecules governing th is PGC-PGC interaction have yet to be identified.