The dikaryon is a

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: * Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space *Nuclear ...

feature which is unique to certain

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

. (The green alga ''

Derbesia ''Derbesia'' is a genus of green algae in the family Derbesiaceae. The plant was originally known from different names applied to its larger sporophyte, ''Derbesia'', and its less conspicuous gametophyte, ''Halicystis''. ''Derbesia'' was successf ...

'' had been long considered an exception, until the

heterokaryotic A heterokaryon is a multinucleate cell that contains genetically different nuclei. Heterokaryotic and heterokaryosis are derived terms. This is a special type of syncytium. This can occur naturally, such as in the mycelium of fungi during sexual ...

hypothesis was challenged by later studies.) Compatible cell-types can fuse cytoplasms (

plasmogamy Plasmogamy is a stage in the sexual reproduction of fungi, in which the protoplasm of two parent cells (usually from the mycelia) fuse without the fusion of nuclei, effectively bringing two haploid nuclei close together in the same cell. This sta ...

). When this occurs, the two nuclei of two cells pair off and cohabit without fusing (

karyogamy Karyogamy is the final step in the process of fusing together two haploid eukaryotic cells, and refers specifically to the fusion of the two nuclei. Before karyogamy, each haploid cell has one complete copy of the organism's genome. In order for ...

). 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 or ...

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

monokaryon A monokaryon is a fungal mycelium or hypha in which each cell contains a single nucleus. It also refers to a mononuclear spore or cell of a fungus that produces a dikaryon in its life cycle. The formation of a dikaryon is a plesiomorphic character for the subkingdom

Dikarya Dikarya is a subkingdom of Fungi that includes the divisions Ascomycota and Basidiomycota, both of which in general produce dikaryons, may be filamentous or unicellular, but are always without flagella. The Dikarya are most of the so-called "hig ...

, which consists of the

and the

. The formation of croziers in the Ascomycota and of

clamp connection A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of Basidiomycetes fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rec ...

s in the Basidiomycota facilitates maintenance of the dikaryons. However, some fungi in each of these phyla 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 Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''δι- (di-)'' meaning "two" and ''κάρυον (karyon)'' meaning "

nut Nut often refers to: * Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds * Nut (hardware), fastener used with a bolt Nut or Nuts may also refer to: Arts, entertainment, and media Co ...

", referring to the

cell nucleus The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, h ...

References

External links

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

Etymology

See also

References

External links