The American geneticist Barbara McClintock was trained as a botanist, receiving a Ph.D. in botany from Cornell University (1927). McClintock discovered anomalies in pigmentation and other features of corn (Zea Mays) that led her to question the prevailing model of the chromosome as a linear arrangement of fixed genes. Her model of the chromosome involved a process of "transposition." In this process, the chromosome released genes and groups of genes from their original positions (this subprocess is named "dislocation") and reinserted them into new positions. Although her original research was published in the 1930's and 1940's, it was not until research in molecular biology confirmed her… theories that she received wide professional recognition. McClintock was elected to the National Academy at the age of 42 and was elected president of the Genetics Society of America a year later. She received many honorary degrees and other awards, including the Lasker Award and a Nobel Prize. McClintock died after a brief illness at the Carnegie Institution's Cold Spring Harbor Laboratories, where she had lived and worked for 50 years.