| After its entry into the egg cytoplasm, the spermatozoal nucleus, now called the male pronucleus, begins to swell, and its chromosomal material disperses and becomes similar in appearance to that of the female pronucleus. |
| If this is true, the centrosome of the zygote nucleus must be entirely derived from that of the male pronucleus. |
| In fact, occasionally, only one pronucleus is produced, and there is now evidence that suggests, that this pronucleus is diploid. |
| Without to ocytes activation, male pronucleus and female pronucleus unable to formed together into zygote. |
| Before fertilization a type of cell division called a reduction division brings the number of chromosomes in the female pronucleus down to 23, including one X chromosome. |
| Each pronucleus stores the genetic material characteristic of the partner from which it comes, and the combination of these two shall determine the genetic makeup of the new embryo. |
