A '''pronucleus''' is the nucleus of a [[sperm]] or an [[egg]] prior to fertilization. Sperm and egg cells carry half the number of [[chromosome]]s of other nonreproductive cells. When the pronucleus of a sperm fuses with the pronucleus of an egg, their chromosomes combine and become part of a single nucleus in the resulting embryo, containing a full set of chromosomes.
== Sources ==
http://www.genome.gov/glossary.cfm?key=pronucleus
[[Category:Genetics]]