Mating occurs between opposite mating types, resulting in the formation of basidiospores.
On the other hand, no defect in filamentation and sporulation was observed in unilateral crossings with designated strains of the opposite mating type (results not shown).
Only then will evolutionary branching of ecotype and mating type result in the evolution of reproductively isolated and at the same time ecologically differentiated species.
Chemotropic growth of a female hypha (trichogyne) toward a male cell (conidium) of opposite mating-type results in cell and nuclear fusion, followed by meiosis and enlargement of the protoperithecium into the fruiting body (perithecium).
We have previously observed in a restricted number of red yeast species that genomic regions around the PR locus exhibited synteny breaks, gene inversions and sequence divergence between the two mating types as a result of apparent partial suppression of recombination, while synteny was well conserved across species when MAT regions of the same mating type where compared [ 24, 39].
The model proposed by Lee et al. [53] for early steps of mating type formation should result in idiomorphic or allelic sequences of a given mating-type locus containing phylogenetically related genes.
First, we provided evidences that Z. sapae ABT301T possesses four independent mating type-like loci, resulting in an unusual a,α,α,α genotype.
Specifically, sexual spores and vegetative cells in this taxon contain haploid nuclei of both mating types (mat A and mat a), resulting in heterokaryotic individuals capable of completing the life-cycle on their own; a mating-system called pseudohomothallism [ 3, 4].
This resulted in at least 7 apparent mating types or sexes.
PCR reactions were repeated independently, three times, for the two samples identified as mating type a (see Results).
