A pronucleus (pl.: pronuclei) denotes the nucleus found in either a sperm or egg cell during the process of fertilization. The sperm cell undergoes a transformation into a pronucleus after entering the egg cell but prior to the fusion of the genetic material of both the sperm and egg.

原核融合（pronuclei fussion）是指雄性原核和雌性原核发生融合的现象。

The unpacked DNA is enclosed in the slowly forming paternal and maternal pronuclei. During a synthesis phase the duplication of the DNA occurs in them. After the synthesis phase, which takes almost a day, the DNA condenses into chromosomes. These promptly order themselves on the zygote's mitotic spindle so this can divide into the two-cell stage.

Fertilization is not complete, however, until the two haploid nuclei (called pronuclei) have come together and combined their chromosomes into a single diploid nucleus. In fertilized mammalian eggs, the two pronuclei do not fuse directly as they do in many other species.

2021年2月5日 · The mechanisms that then move the pronuclei inwards for their unification are only poorly understood in mammals. Here, we report two mechanisms that act in concert to unite the parental genomes...

In embryology, the nuclear material of the head of the sperm (male pronucleus) or of the oocyte (female pronucleus), after the oocyte has been penetrated by the sperm; each pronucleus normally carries a haploid set of chromosomes, so that the merging of the pronuclei in fertilization reestablishes diploidy.

The pronuclei (singular: pronucleus) are the initial male and female nuclei, containing their respective genetic material, that occur in the early zygote. These two haploid nuclei fuse to form the diploid nucleus of the late zygote.

我们通常把这个时候所谓的“核”称为原核(pronuclei)——吸出来；B：已经吸了出来；C：注入与被吸出来的原核异性的另外一个原核；D：已经注入。 有一堆科学家进行了这个实验。

The pronuclei are far from merely a passive staging area for the two parental genomes prior to assembling the zygotic genome. Both sets of chromatin undergo asynchronous DNA synthesis at pronuclear stage, generating the 4C amount of DNA required for the ensuing first mitosis.

The two pronuclei, one from each parent, prepare to combine genetic material and establish the foundation for the new organism's genetic identity. A pronucleus is the haploid nucleus of a sperm or egg cell following fertilization, before the fusion of these nuclei occurs to form a diploid zygote.