Objective To investigate the relationship between the first polar body morphology of oocyte and the zygote morphology in pronucleus stage, embryo quality in cleavage stage.
When the membranes of the two pronuclei rupture, chromosomes go flying, and boom, you officially have a diploid zygote, which almost immediately starts mitosis.
Meanwhile, the sperm's detached nucleus swells up to five times its original size, forming the male pronucleus, one of two sort of proto-nuclei that contain each gamete's genetic information.
The other one, the female pronucleus, takes shape from the nucleus of the ovum, and then the two then start to approach each other, pulled along a protein scaffolding, or mitotic spindle, between the two.