Most sexes within one species

In some fungi, two different genes yield the (two) different sexes (as in animals and plants), but in certain other fungi each of these two genes can have several different versions (alleles), thereby resulting in many more than the normal two different sexes (male and female) existing. The greatest number of different sexes recorded from a single species is just over 28,000 – as documented from the split gill fungus Schizophyllum commune, an extremely common mushroom species of global distribution. This is because one of its two sex genes has more than 300 alleles, and the other has more than 90, thereby yielding more than 28,000 different allele combinations, and therefore sexes, via these two genes.

By producing such a vast array of different sexes, this species guarantees a vast diversity of outbreeding, thereby minimising deleterious mutations from occurring (which is a common occurrence in inbreeding), but maximising morphological and genetic variety for overcoming external challenges caused by environmental changes.