Share this entry
pronucleus Syllabification: pro·nu·cle·us
Pronunciation: /prōˈn(y)o͞oklēəs/

Definition of pronucleus in English:

noun (plural pronuclei-klēˌī)

Either of a pair of gametic nuclei, in the stage following meiosis but before their fusion leads to the formation of the nucleus of the zygote.
Example sentences
  • In normal fertilisation the formation of male and female pronuclei is an important stage just before the maternal and paternal chromosomes start to pair up in preparation for the first cell division.
  • The sperm and egg pronuclei form the zygotic nucleus.
  • Diploid zygotes created by combining a male and a female pronucleus gave rise to viable embryos, but combining two male or two female pronuclei did not.


Pronunciation: /prōˈn(y)o͞oklēər/
Example sentences
  • Arrowheads point to sister chromatids and refer to chromosome replication during the pronuclear stage.
  • In mice and humans, the pronuclear membranes disappear before the pronuclei come together.
  • In contrast, wisp embryos arrest after completion of meiosis II, before pronuclear fusion.
Definition of pronucleus in:
Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Subscribe to remove adverts and access premium resources