Homoeosis

a change in an organ or segment of the body, in which the organ becomes similar to the homologous organ or segment of the body of an organism in a phylogenetically related group. The term “homoeosis” was proposed by the English scientist W. Bateson in 1894. Homoeosis is most frequently found in insects. The study of this phenomenon has made possible the discovery of new facts that are important to embryology and comparative anatomy. Homoeosis may be caused by nonhereditary disturbances in development and by homoeotic mutations (for example, in Drosophila, mutations discovered by the Soviet scientists B. L. Astaurov and E. I. Balkashina in 1929).