Definition of pronucleus in English:



  • 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.

    • ‘The sperm and egg pronuclei form the zygotic nucleus.’
    • ‘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.’
    • ‘For instance, the migration of the male pronucleus within the animal oocyte after fertilization, together with movements of the female pronucleus, are essential events for nuclear fusion.’
    • ‘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.’
    • ‘Meiotic spindle poles of mutant embryos are not as well focused as wild type, and meiotic failure often leads to multiple maternal pronuclei as compared to wild type.’