Mating type
Encyclopedia
Mating types occur in eukaryote
s that undergo sexual reproduction
via isogamy
. Since the gamete
s of different mating types look alike, they are often referred to by numbers, letters, or simply "+" and "-" instead of "male" and "female." Mating (fertilization or conjugation) can only take place between different mating types.
Isogamic reproduction via mating types is especially prevalent in fungi
. Ascomycetes usually have two mating types referred to as "+" and "-" or in the case of yeast as "a" and "α" (alpha). Basidiomycetes on the other hand can have thousands of different mating types.
Nothing in the morphology
reveals that the cells or hyphae are either "+" or "-" but they are distinguished as being two forms of the same species. Mating types differ genetically by having two or more distinct allele
s at a mating-type region
in their genome. These genes typically code for cell surface components that are important in the interaction between different mating types. This interaction between different components is necessary to have sexual reproduction
.
Eukaryote
A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear...
s that undergo 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...
via isogamy
Isogamy
Isogamy is a form of sexual reproduction that involves gametes of similar morphology , differing only in allele expression in one or more mating-type regions...
. Since the gamete
Gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...
s of different mating types look alike, they are often referred to by numbers, letters, or simply "+" and "-" instead of "male" and "female." Mating (fertilization or conjugation) can only take place between different mating types.
Isogamic reproduction via mating types is especially prevalent in fungi
Fungus
A fungus is a member of a large 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, Fungi, which is separate from plants, animals, and bacteria...
. Ascomycetes usually have two mating types referred to as "+" and "-" or in the case of yeast as "a" and "α" (alpha). Basidiomycetes on the other hand can have thousands of different mating types.
Nothing in the morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
reveals that the cells or hyphae are either "+" or "-" but they are distinguished as being two forms of the same species. Mating types differ genetically by having two or more distinct allele
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
s at a mating-type region
Mating-type region
The mating-type region is a specialized region in the genomes of some yeast and other fungi, usually organized into heterochromatin and possessing unique histone methylation patterns. The genes in this region regulate the mating type of the organism and therefore determine key events in its life...
in their genome. These genes typically code for cell surface components that are important in the interaction between different mating types. This interaction between different components is necessary to have 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...
.
- Each mating type can signal its presence to others, (the "female" signals the "male" first by definition). This is done using pheromonePheromoneA pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
s, steroidSteroidA steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...
s, or carotenoidCarotenoidCarotenoids are tetraterpenoid organic pigments that are naturally occurring in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, some bacteria, and some types of fungus. Carotenoids can be synthesized fats and other basic organic metabolic building...
s. - In addition to "male" and "female," there may also be a distinction between strong and weak (e.g. strong female). In saccharomycesSaccharomycesSaccharomyces is a genus in the kingdom of fungi that includes many species of yeast. Saccharomyces is from Greek σάκχαρ and μύκης and means sugar fungus. Many members of this genus are considered very important in food production. One example is Saccharomyces cerevisiae, which is used in making...
, there is a very complex system of mating type alternation from alpha to a through genetic recombinationGenetic recombinationGenetic recombination is a process by which a molecule of nucleic acid is broken and then joined to a different one. Recombination can occur between similar molecules of DNA, as in homologous recombination, or dissimilar molecules, as in non-homologous end joining. Recombination is a common method...
.