The majority of injected oocytes, however, were completely activated because they were released from MII arrest and had formed the female pronucleus
(Figures 2A-C, E, F; Table 1).
Concurrent with sperm fusion, meiosis is reinitiated from metaphase I arrest, polar bodies form, and the female pronucleus
Examination of the transparent eggs of Beroe revealed that several sperm typically penetrate the ovum (polyspermy) and that the female pronucleus
then moves around within the ovum to each of the male pronuclei in turn before fusing with one of them.
The hydatidiform mole is a uterine tumor that occasionally develops in which the fetus is absent and the placental tissue is abnormally large, arising most often from a sperm's fertilizing an ovum in which the female pronucleus
In addition, the cytological studies revealed that the donor sperm incorporated into the egg cytoplasm, developed into the male pronucleus, and merged with the female pronucleus
eventually in some interspecific crosses in molluscs, such as C.
Activated eggs do not form blisters of cytoplasm when removed from cold treatment, although a small crescent of cytoplasm may form over the female pronucleus
after 50 minutes.