title: Corrections and clarifications.
abstract: In the article " Evidence found for a possible ' aggression gene' " by Virginia Morell (Research News, 18 June, p. 1722), the collaborative teams of Peter Seeburg at the University of Heidelberg, Germany; Jean Shih at the University of Southern California; and Creed W. Abell at the University of Texas, Austin, should also have been credited with cloning the human monoamine oxidase (MAO) A and B genes. Seeburg and his colleagues published their research in the July 1988 issue of the Proceedigs of the Nationl Acaderny of Sciences. Xandra Breakefield and her colleagues reported their cloning of the MAO A gene in the October 1988 issue of the Joumal of Neurochemistry. Although Breakefield's group also cloned the MAO B gene, they did not publish this research.