Primordial Germ Cells (GnR)

Primordial germ cells (PGCs) migrate toward the genital ridges via the hindgut and dorsal mesentery.  Once PGCs enter the genital ridge, they lose their ability to migrate. Before entry of PGCs into the genital ridge, XX and XY PGCs function identically in all aspects. The first mechanistic difference between an XX and an XY germ cell in the genital ridge is reactivation of the inactive X in the female PGCs. After this point, there is a major change in the fate of these PGCs.