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

/pro·nu·cle·us/ (-noo´kle-us)
1. the precursor of a nucleus.
2. the haploid nucleus occurring after meiosis in a germ cell.

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.

pronucleus

[-no̅o̅′klē·əs] pl. pronuclei
Etymology: Gk, pro + L, nucleus, nut kernel
the nucleus of an ovum or a spermatozoon after fertilization but before fusion of the chromosomes to form the nucleus of the zygote. Each pronucleus contains the haploid number of chromosomes, is larger than the normal nucleus, and is diffuse in appearance. The pronucleus of the ovum is formed only after it has completed its second meiotic division and the second polar body has formed, which occur after the spermatozoon has penetrated. It then loses its nuclear envelope, releasing the chromosomes so that synapsis with the chromosomes of the male pronucleus, which is contained in the head of the spermatozoon, can occur. Also called germinal nucleus, germ nucleus. See also oogenesis, spermatogenesis.

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.

pronucleus

pl. pronuclei; the haploid nucleus of a sex cell.

female pronucleus
the haploid nucleus of the fully mature ovum 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 ovum and acquired a pronuclear membrane.