The dikaryon (karyogamy) is a

cell nucleus The cell nucleus (; : nuclei) is a membrane-bound organelle found in eukaryote, eukaryotic cell (biology), cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have #Anucleated_cells, ...

feature that is unique to certain

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

. (The green alga '' Derbesia'' had been long considered an exception, until the heterokaryotic hypothesis was challenged by later studies.) Compatible cell-types can fuse cytoplasms ( plasmogamy). When this occurs, the two nuclei of two cells pair off and cohabit without fusing ( karyogamy). This can be maintained for all the cells of the

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

by synchronously dividing so that pairs are passed to newer cells. In the

Ascomycota Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The def ...

this attribute is most often found in the ascogenous hyphae and ascocarp while the bulk of the mycelium remains monokaryotic. In the

Basidiomycota Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

this is the dominant phase, with most Basidiomycota monokaryons weakly growing and short-lived. Fungus cell cycle-en

The formation of a dikaryon is a plesiomorphic character for the subkingdom Dikarya, which consists of the

and the

. The formation of croziers in the Ascomycota and of clamp connections in the Basidiomycota facilitates maintenance of the dikaryons. However, some fungi in each of these

phyla Phyla, the plural of ''phylum'', may refer to: * Phylum, a biological taxon between Kingdom and Class * by analogy, in linguistics, a large division of possibly related languages, or a major language family which is not subordinate to another Phy ...

have evolved other methods for maintaining the dikaryons, and therefore neither croziers nor clamp connections are ubiquitous in either phylum.

Etymology

The name ''dikaryon'' comes from the Greek ''δι- (di-)'' meaning "two" and ''κάρυον (karyon)'' meaning " nut", referring to the

References

External links

Fungi Online Page, Formation of Dikaryons
Mycology {{Mycology-stub

Etymology

See also

References

External links