Mating Type

Mating types are molecular mechanisms that regulate compatibility in sexually reproducing eukaryotes. They occur in isogamous and anisogamous species. Depending on the group, different mating types are often referred to by numbers, letters, or simply "+" and "-" instead of "male" and "female", that refer "sexes" or differences in size between gametes. Syngamy can only take place between gametes carrying different mating types.

Reproduction regulated by mating types is especially prevalent in fungi. Ascomycetes usually have two mating types referred to as "Mat 1-1" and "Mat 1-2" or in the case of yeast as "a" and "α" (alpha). Mating type genes in ascomycetes are called idiomorphs rather than alleles due to the uncertainty of the origin by common descent. The proteins they encode are transcription factors that regulate both the early and late stages of the sexual cycle. Heterothallic ascomycetes produce gametes that present a single Mat idiomorph and syngamy will only be possible between gametes carrying complementary mating types. On the other hand, homothallic ascomycetes produce gametes that can fusion with every other gamete in the population (including its own mitotic descendants) most often because each haploid contains the two alternate forms of the Mat locus in its genome. Basidiomycetes on the other hand can have thousands of different mating types.

Famous quotes containing the words mating and/or type:

    The elephant, not only the largest but the most intelligent of animals, provides us with an excellent example. It is faithful and tenderly loving to the female of its choice, mating only every third year and then for no more than five days, and so secretly as never to be seen, until, on the sixth day, it appears and goes at once to wash its whole body in the river, unwilling to return to the herd until thus purified. Such good and modest habits are an example to husband and wife.
    St. Francis De Sales (1567–1622)

    It took six weeks of debate in the Senate to get the Arms Embargo Law repealed—and we face other delays during the present session because most of the Members of the Congress are thinking in terms of next Autumn’s election. However, that is one of the prices that we who live in democracies have to pay. It is, however, worth paying, if all of us can avoid the type of government under which the unfortunate population of Germany and Russia must exist.
    Franklin D. Roosevelt (1882–1945)