Here we describe procedures for the selection of diploid  Schizosaccharomyces pombe  ade6-M210/ade6-M216  heteroallelic complementation is widely used to select for Ade +  diploids. Such diploids will readily sporulate when starved of nitrogen. For some investigations, stable diploids are preferable (e.g., for genetic complementation tests), and in these cases mating an  h -   strain with an  h 90  mat2-Pi-102  strain can be used to prevent sporulation. When  ade6-M210/ade6-M216  mutations impact on, or show synthetic interactions with, the gene of interest, two different auxotrophic markers can be used to select complementation.