Intersection type

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A hybrid type or mating type is understood in fungi as a self-incompatibility system that prevents the creation of descendants of genetically identical or similar parents regardless of gender.

In fungi, the sex is defined according to which cell of the mycelium donates the nucleus ("male") and which receives the nucleus ("female"). Fungi, whose mycelia only develop nuclear donor cells or only nucleus recipient cells, are therefore unisexual and they are called dioecious (dioecious). In contrast, there are monoecious fungi whose mycelia contain both nuclear donor cells and nuclear recipient cells.

The crossing types determine which cells are compatible with each other, regardless of gender. Sex cells can only fuse with each other if they are of different sexes and are also different types of crosses. In the case of higher fungi ( Dikarya ), the crossing factor is determined by the “mating-type locus ” ( MAT for short ).

With some groups of mushrooms (e.g. with some stand mushrooms ) there are not just two types of crosses, but several. This is realized by the fact that there are several alleles from the MAT locus . There are also higher mushrooms such as B. the Maisbeulenbrand , in which there is not just one, but two independent mating-type Loci a and b . One then speaks of “bipolar junction type loci” or “tetrapolar junction type loci”. A and b locus are coded on two different pairs of chromosomes . Both MAT loci have to be different in order to mate, so that statistically only a quarter of the individuals can be considered as mating partners.

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