However, the chief benefit of mating type switching may be its capacity to allow strains to purge their diploid genomes of deleterious recessive mutations by going through a transient haploid phase, with subsequent homozygous diploids generated from the viable haploid segregants.

How do yeast switch mating types?

Mating type is determined by a single locus, MAT, which in turn governs the sexual behaviour of both haploid and diploid cells. Through a form of genetic recombination, haploid yeast can switch mating type as often as every cell cycle.

What are the mating types in yeast?

Individual yeast cells in these species belong to one of two mating types, known as 'a' and 'α', and mating occurs when a cell of one type fuses with a cell of the other type. However, if a cell is isolated from potential mating partners, it can 'switch' to the other type and self-mate with its own daughter cell.