Mullerian

Müllerian (also spelled Mullerian in English contexts) is an adjective used in biology and medicine to refer to structures or concepts named after a person with the surname Müller. The most common uses occur in embryology, anatomy, and evolutionary biology.

In anatomy and embryology, the term is associated with the Müllerian ducts, also known as the paramesonephric ducts. In the developing embryo, these ducts give rise to the internal female reproductive tract, including the fallopian tubes, uterus, cervix, and the upper portion of the vagina. In typical male development, the Müllerian ducts regress under the influence of anti-Müllerian hormone.

Clinically, Müllerian agenesis, or Mayer-Rokitansky-Küster-Hauser syndrome (MRKH), is a congenital condition characterized by absence or underdevelopment of the uterus and the upper vagina, with normal functioning ovaries and secondary sexual characteristics.

In evolutionary biology, Müllerian mimicry describes a form of mimicry in which two or more unpalatable or harmful species share common warning coloration or signals. This mutual resemblance reinforces avoidance behavior by predators. Müllerian mimicry differs from Batesian mimicry, in which a harmless species imitates a harmful one.

The term also appears in various eponymous contexts and is commonly written with an umlaut (Müllerian) in European usage; English texts frequently render it as Mullerian.