I am trying to understand the mating behavior of a particular species of fungi known as Schizophyllum commune, or the split-gill.
I found a blog post that explains the mechanisms that define the mating types (or sexes) of this species (there are about 28,000 sexes): http://www.creativewi.re/2017/11/this-fungus-species-has-more-than-23000.html
The post says that the fungus' mating type is defined by a set of two genes that are present on two loci on the chromosomes. Each of these two genes has two alleles. Again, each allele has a number of variations. For example, a fungus with the A1 allele at locus A, and the B2 allele at locus B has the A1B2 mating type. This is a simplified example that doesn't include the alleles' variations.
Now, my question is as follows: what is the number of these alleles' variations at each locus, and how did the scientists count the total number of sexes?