Microsurgical enucleation of a single pronucleus from each of three tripronuclear zygotes was performed and the embryos were transferred to a 38-year-old woman on day 3 after fertilization. A normal healthy baby boy was born at 38 weeks and 4 days gestation, demonstrating that with polyspermic fertilization, removal of the extra male pronucleus allows the zygote to develop normally.

During meiosis in fission yeast, the zygote nucleus undergoes microtubule-driven oscillatory movements that ultimately serve to promote genetic recombination. An essential component of this is a meiosis-specific consolidation of microtubule-organizing activity to the the spindle pole body, driven by the novel coiled-coil protein mcp6/hrs1p.