Thus, from the gene to the character, and back from the typical character (standard conidium) to the gene, we have traced a few of the biosynthetic pathways which must obligatorily be triggered (switched on or off) to effect the transition from the relatively undifferentiated vegetative hyphae through the fertile, conidiogenous hyphae to the differentiated cells, the conidia. There is good promise that further, deeper studies will finally revealNeurospora to have one of the most highly integrated control systems for eucaryotic sporogenesis when considered as a model of cell differentiation.