Figure 5.

Pheromone/Receptor (PR) mating-type locus in Basidiomycetes. (a) Schematic representation of a system comparable to Ustilago maydis in which each of the two mating-type alleles at the PR locus carries one receptor and one pheromone gene. Each pheromone is compatible with the receptor of the other mating type. (b) System comparable to the Schizophyllum commune PR mating-type locus, which is composed of two sub-loci that each carries one receptor and a variety of pheromone genes. The receptor of each sub-locus is activated by at least one pheromone of any other mating-type allele. Interaction at one sub-locus is sufficient for compatibility. Between the sub-loci a recombination hotspot is located. (c) A system that is composed of three sub-loci comparable to Coprinopsis cinerea.