Pronuclei, nucleus of the ovum or the spermatozoon after fertilization but before fusion of the pronuclei to form the nucleus of the zygote. Each pronucleus contains the haploid chromosome number.
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.
The haploid nucleus of either the ovum or spermatozoon prior to their union in fertilization.