What is the Difference Between Homothallic and Heterothallic Fungi?

The main difference between homothallic and heterothallic fungi lies in their mating and reproduction processes:

• Homothallic fungi are self-fertile, meaning they can sexually reproduce with a single individual without the need for a compatible partner. These fungi can produce sexual progeny without outcrossing, which reduces genetic variability in the offspring. Examples of homothallic fungi include Neurospora africana and N. galapagosensis.
• Heterothallic fungi are self-sterile and require two compatible partners for mating to occur. They reproduce by outcrossing, which increases genetic variability in the progeny. Neurospora crassa is an example of a heterothallic fungal species.

Some heterothallic fungi can exhibit homothallism under specific environmental conditions, and transitions between heterothallic and homothallic patterns of sexuality are common throughout the fungal kingdom. In fact, the last eukaryotic common ancestor (LECA) of fungi is widely accepted to have been sexual, and both homothallic and heterothallic mating modes can be observed in different species of the same genus.

Comparative Table: Homothallic vs Heterothallic Fungi

Here is a table comparing the differences between homothallic and heterothallic fungi:

Homothallic fungi rely on self-fertilization, while heterothallic fungi perform outcrossing, which increases the genetic variability in the progeny fungi. In homothallic fungi, both the MAT1-1 and MAT1-2 idiomorphs are present in the genome, allowing them to complete the sexual cycle without the need for a partner. In contrast, heterothallic fungi require two compatible mating types to undergo sexual reproduction.