A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum

Septum

In anatomy, a septum is a wall, dividing a cavity or structure into smaller ones.-In human anatomy:...

, or segment of hypha separated by crossed walls, receives a set of differing nuclei

Cell nucleus

In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

, which are obtained through mating of hyphae of differing sexual types. It is used to create genetic variation

Genetic variation

Genetic variation, variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the “raw material” for natural selection. Genetic variation is brought about by mutation, a change in a chemical structure of a gene. Polyploidy is an...

 within the hypha much like the mechanisms found in crozier

Crozier (mycology)

A crozier is an anatomical feature of many fungi in the phylum Ascomycota that form at the base of asci and look like hook-topped shepherd’s staffs or stylized religious crosiers...

 during sexual reproduction

Sexual reproduction

Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...

.

Formation

Clamp connections are formed by the terminal hypha during elongation. Before the clamp connection is formed this terminal septa contains two nuclei (depicted as green and orange circles in Figure 3). Once the terminal septa is long enough it begins to form the clamp connection. At the same time each nuclei undergoes mitotic division to produce two daughter cells. As the clamp continues to develop it uptakes one of the daughter (green circle) cells produced and separates it from its sister cell. While this is occurring the remaining nuclei (orange circles) begin to migrate from one another to opposite ends of the cell. Once all these steps have occurred a septum

Hypha

A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...

 forms, separating each set of nuclei.

Use in classification

Clamp connections are structures unique to the phylum Basidiomycota

Basidiomycota

Basidiomycota is one of two large phyla that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi...

. Many fungi from this phylum produce spores in basidiocarp

Basidiocarp

In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...

s (fruit bodies, that is the mushrooms), above ground. Though clamp connections are exclusive to this phylum, not all species Basidiomycota possess these structures. As such, the presence or absences of clamp connections has been a tool in categorizing genera

Genera

Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...

 and species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

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