Lysenkoism is a term given to the repressive political and social campaigns undertaken in science and agriculture by the powerful Stalinist director of the Soviet Institute of Genetics, Trofim Denisovich Lysenko and his followers, which began in the late 1920s and formally ended in 1964. Lysenkoism, or Lysenko-Michurinism, may also denote the biological inheritance principles Lysenko subscribed to which derive from theories of the heritability of acquired characteristics a body of biological inheritance theory which departs from Mendelism and that Lysenko himself named "Michurinism".