pronucleus

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Related to Male pronucleus: Female pronucleus

pronucleus

 [pro-noo´kle-us]
the haploid nucleus of a germ cell.
female pronucleus the haploid nucleus of the fully mature oocyte, which loses its nuclear envelope and liberates its chromosomes to meet the synapsis with those from the male pronucleus.
male pronucleus the nuclear material of the head of a spermatozoon, after it has penetrated the oocyte and acquired a pronuclear membrane.

pro·nu·cle·us

, pl.

pro·nu·cle·i

(prō-nū'klē-ŭs, -klē-ī),
1. One of a pair of nuclei undergoing fusion in karyogamy.
2. 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.

pronucleus

(prō-no͞o′klē-əs, -nyo͞o′-)
n. pl. pronu·clei (-klē-ī′)
The haploid nucleus of a sperm or egg before fusion of the nuclei in fertilization.

pro·nu′cle·ar adj.

pro·nu·cle·us

, pl. pronuclei (prō-nū'klē-ŭs, -ī)
1. One of a pair of nuclei undergoing fusion in karyogamy.
2. 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 the diploidy.
References in periodicals archive ?
At this time, duplicated centrosomes migrated to opposite sides of the male pronucleus (Fig.
This study was aimed to evaluate the xenogenic dog sperm in formation of male pronucleus following injection into the sheep oocytes.
After axonemal incorporation and nuclear translocation, the sperm chromatin decondenses and is encompassed by a membrane forming the male pronucleus. Concurrent with sperm fusion, meiosis is reinitiated from metaphase I arrest, polar bodies form, and the female pronucleus develops.
First, a fertilizing sperm takes on a species-specific conformation inside embryos that may serve a role in positioning the male pronucleus before karyogamy (Karr 1991).
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.
First cleavage occurs along the line between the polar bodies and the apex of the embryo where the male pronucleus enters the egg.