John White’s work has led to an understanding of the complete pattern of synaptic connectivity of the nematode Caenorhabditis elegans. He identified the first gene with a demonstrated role in determining synaptic specificity. He studied the role of cell–cell interaction in determining the lineage pattern, stimulating a wide field of research. In more recent work, John and his co-workers partially confirmed his earlier model of cytokinesis; they discovered genes controlling cytokinesis and found features previously thought specific to plant cell division. Recognising the potentialities of laser-scanning confocal microscopy, John built a prototype microscope: with Brad Amos he developed this into a commercially produced instrument now widely used, which was distinguished by the Mullard Award of the Royal Society and other awards.