Homothallism

Part of speech: noun

Definitions

1. A reproductive mechanism found in specific fungi and algae where an organism can mate with itself, leading to the production of offspring from a single genetic lineage
2. An occurrence in certain fungal and algal species where self-fertilization allows for reproduction without the contribution of a genetically different partner
3. A reproductive strategy in some fungi and algae where one organism produces offspring independently by mating with itself

Etymology: Homothallism is a modern scientific coinage, built from Greek roots rather than from any ancient usage. "Homo-" comes from Greek "homos," meaning "same," and "thallos," meaning "green shoot" or "young branch," a root that gave the English "thallus," the plant body of algae and fungi that lacks true stems and leaves. Mycologists and botanists formed the term to describe fungi whose individual thalli can produce both mating types, so a single organism can cross with itself. The contrast term is heterothallism, where separate individuals must be of different mating types to reproduce sexually. Homothallism is therefore not a self-fertilizing process in the animal or flowering-plant sense, but a sexual system that happens to need only one partner. Some species do this through genuinely distinct mating-type genes within one strain, while others pair nuclei from a single thallus in a different way.