Yeast mating type is determined by the genotype at the mating type locus (MAT). In homothallic (self-fertile) Saccharomycotina such as Saccharomyces cerevisiae and Kluveromyces lactis, high-efficiency switching between a and α mating types enables mating. Two silent mating type cassettes, in addition to an active MAT locus, are essential components of the mating type switching mechanism. In thi...

Fungi form one of the most ubiquitous and successful kingdoms of life on Earth. There are more than 100,000 known species of fungi, divided into four phyla — ascomycetes, basidiomycetes, zygomycetes and chytrids — and these have populated a vast array of biological niches, including those that are pathogens of animals (including humans and insects), plants and even other microorganisms. The mor...

The unicellular eukaryote Tetrahymena thermophila has seven mating types. Cells can mate only when they recognize cells of a different mating type as non-self. As a ciliate, Tetrahymena separates its germline and soma into two nuclei. During growth the somatic nucleus is responsible for all gene transcription while the germline nucleus remains silent. During mating, a new somatic nucleus is dif...

Fungal populations that reproduce sexually are likely to be genetically more diverse and have a higher adaptive potential than asexually reproducing populations. Mating systems of fungal species can be self-incompatible, requiring the presence of isolates of different mating-type genes for sexual reproduction to occur, or self-compatible, requiring only one. Understanding the distribution of ma...

Saccharomyces cerevisiae, baker’s yeast, can exist in either a haploid (1n) or a diploid (2n) state. Haploids express one of two mating types, a or a (alpha). Haploids of either mating type are capable of mating with haploids of the opposite mating type in response to the action of mating pheromones. Mating results in fusion of haploid cells, forming an a/a diploid, which is no longer capable o...

In most heterothallic mushroom species, inbreeding is avoided by an incompatibility system determined by two loci each with multiple alleles (the A and B mating-type loci). In this study we investigated the genetic structure of the mating-type loci in the tropical oyster mushroom Pleurotus djamor using both positional cloning and degenerate PCR methods. DNA sequences from genomic regions cosegr...

About 15,000 species of ascomycete fungi lack a known sexual state. For fungi with asexual states in the anamorph genera Embellisia, Ulocladium, and Alternaria, six species have known sexual states but more than 50 species do not. In sexual filamentous ascomycetes, opposite mating type information at the MAT1 locus regulates mating and the opposite mating type genes each have a clonal, non-reco...