Akademik

Pronucleus
A cell nucleus with a haploid set of chromosomes (23 chromosomes in humans) resulting from meiosis (germ-cell division). The male pronucleus is the sperm nucleus after it has entered the ovum at fertilization but before fusion with the female pronucleus. Similarly, the female pronucleus is the nucleus of the ovum before fusion with the male pronucleus.
* * *
1. One of a pair of nuclei undergoing fusion in karyogamy. 2. In embryology, the nuclear material of the head of the spermatozoon (male p.) or of the ovum (female p.), after the ovum has been penetrated by the spermatozoon; each p. normally carries a haploid set of chromosomes, so that the merging of the pronuclei in fertilization reestablishes diploidy.

* * *

pro·nu·cle·us (')prō-'n(y)ü-klē-əs n, pl -clei -klē-.ī also -cle·us·es the haploid nucleus of a male or female gamete (as an egg or sperm) up to the time of fusion with that of another gamete in fertilization see FEMALE PRONUCLEUS, MALE PRONUCLEUS

* * *

n. (pl. pronuclei)
the nucleus of either the ovum or spermatozoon after fertilization but before the fusion of nuclear material. The pronuclei are larger than the normal nucleus and have a diffuse appearance.

* * *

pro·nu·cle·us (pro-nooґkle-əs) the haploid nucleus occurring after meiosis in the germ cells.

Medical dictionary. 2011.