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.

Look at other dictionaries:

  • pronucléus — [ pronykleys ] n. m. • 1875; de pro et nucléus ♦ Biol. Noyau haploïde d un œuf fécondé. Pronucléus mâle, femelle. ● pronucléus nom masculin Noyau du spermatozoïde (pronucléus mâle) ou de l ovule (pronucléus femelle). pronucléus [pʀonykleys] n. m …   Encyclopédie Universelle

  • Pronucleus — Pro*nu cle*us, n.; pl. {Pronuclei} ( [imac]). [NL. See {Pro }, and {Nucleus}.] (Biol.) One of the two bodies or nuclei (called male and female pronuclei) which unite to form the first segmentation nucleus of an impregnated ovum. [1913 Webster]… …   The Collaborative International Dictionary of English

  • pronucleus — pronucleus. См. пронуклеус. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Pronuclĕus — Pronuclĕus, Spermakern, s. Befruchtung …   Meyers Großes Konversations-Lexikon

  • pronucleus — [prō no͞o′klē əs, prōnyo͞o′klē əs] n. pl. pronuclei [prō no͞o′klēī΄, prōnyo͞o′klēī΄] [ModL: see PRO 1 & NUCLEUS] Zool. the haploid nucleus of either the spermatozoon or the ovum which unite in fertilization to form the fused double (or diploid)… …   English World dictionary

  • pronucleus — Haploid nucleus resulting from meiosis. In animals the female pronucleus is the nucleus of the ovum before fusion with the male pronucleus. The male pronucleus is the sperm nucleus after it has entered the ovum at fertilization but before fusion… …   Dictionary of molecular biology

  • Pronucleus — The process of fertilization in the ovum of a mouse. A pronucleus (plural: pronuclei) is the nucleus of a sperm or an egg cell during the process of fertilization, after the sperm enters the ovum, but before they fuse. Sperm and egg cells are… …   Wikipedia

  • pronucleus — noun Etymology: New Latin Date: 1880 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 …   New Collegiate Dictionary

  • pronucleus — n. [L. pro, before; nucleus, kernal] The spermatozoa and ova nucleus after maturation, prepared for fusion to form a zygote nucleus …   Dictionary of invertebrate zoology

  • pronucleus — /proh nooh klee euhs, nyooh /, n., pl. pronuclei / klee uy /. Cell Biol. either of the gametic nuclei that unite in fertilization to form the nucleus of the zygote. [1875 80; < NL; see PRO 1, NUCLEUS] * * * …   Universalium

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.