The significance of genetics in biology today stems to a considerable extent from the knowledge which has been obtained through the use of fungi as experimental objects. As a result of their short generation time, their ease of culture under laboratory conditions, and the possibil ity of identifying the four products of meiosis through tetrad analysis, the fungi have proven themselves in many ways superior to the classic genetic experimental material such as Drosophila and maize. Because they permit investigation of genetic fine structure as well as biochemical analysis of the function of the...