There are some 25,000 species of Deuteromycota, or imperfect fungi, so called because their manner of reproduction is asexual and not understood. These fungi include numerous molds, one of which is the source of penicillin. Other variants cause fungal infection of the feet, jock itch and ringworm. Some species of the genus Deuteromycota are important for making Camembert, Roquefort and blue cheese.
The life cycle of all living organisms ultimately is based on their manner of reproduction. Males of both plants and animals behave one way; females behave in another. Deuteromycota (Greek for "second fungi"), is the name of a diverse group fungi that produce only asexual spores. The case of Deuteromycota is anomalous because researchers do not know how they reproduce; hence, the details of their life cycle is not understood.
The Perfect Phase
Mycologists refer to the sexual reproduction of a fungus as the "perfect phase." However, the sexual reproduction of Deuteromycota, a heterogeneous group of species of fungi that are otherwise unrelated to one another, never have been observed.
A Botanical Mystery
Because the sexual reproduction critical to understanding the origins and growth of any organism, including fungi, the life cycle of Deuteromycota remains unknown, a botanical mystery. Mycologists speculate that Deuteromycota have lost their sexual phase though the course of evolution, but this theory is unproved. It also is possible that researchers have been unable to replicate the right environmental conditions to observe the sexual phase.
Similarities to Other Fungi
Deuteromycota have long, threadlike tissues that form the body of club fungi and sac fungi. Their fine, branching tubes contain asexual spores. In this respect, they appear to be fungi. These asexual spores, conidia, are not produced by a sporangium, the source of spores produced by other fungi, but they do resemble the spores in the sexual phase of sac fungi.
DNA of Deuteromycota
The general relationship of species of Deutermycota to known fungi has been established by comparative analysis of their DNA sequences. But the critical function to their growth cycle and the details of how they reproduce themselves remain elusive.