FIGURE 2.

Representative mating type loci from the Ascomycota. (A) The organization of the mating-type loci of Saccharomyces cerevisiae serves as the model for the group, containing homeodomain proteins that regulate the expression of other mating type-specific genes. (B) Although not as well characterized as Sa. cerevisiae, Neurospora crassa exists as two haploid mating types, each of which contain genetic information at the mating type loci to govern expression of mating type specific genes. (C) Like Sa. cerevisiae, Schizosaccharomyces pombe contains homeodomain proteins at its mating type loci consisting of both expressed and donor regions. (D) Although most clinical isolates are diploid, Candida albicans does have two different mating type loci found in two haploid strains that can be cultivated in the laboratory setting. Boxes of the same color represent corresponding components in the different mating types.