 Several Ascomycota species are not known to have a sexual cycle.Such asexual species may be able to undergo genetic recombination between individuals by processes involving "heterokaryosis" and "parasexual" events.Parasexuality refers to the process of heterokaryosis, caused by merging of two hyphae belonging to different individuals, by a process called "anastomosis", followed by a series of events resulting in genetically different cell nuclei in the mycelium.