part of part of immediately preceded by immediately preceded by occurrent oogenesis period fully grown oocyte with off-centered germinal vesicle stage fully grown oocyte with no nucleus stage A developing female gamete in which the germinal vesicle has broken down. The germinal vesicle is no longer visible. However, the female gamete is still not mature. It is undergoing meiotic maturation, extruding successively a first and a second polar body. ecao_developmental_stage