McClintock, Barbara (1902–92)

American geneticist who won the 1983 Nobel Prize in Physiology or Medicine for her discovery of genetic transposition, or the ability of genes to change position on the chromosome. Throughout her career, McClintock worked on maize cytogenetics, demonstrating many fundamental genetic concepts including genetic recombination during meiosis.

Barbara McClintock was born on June 16, 1902, in Hartford, Connecticut. When she was six, her family moved to Brooklyn, New York. She graduated from Erasmus Hall High School in 1919 and obtained her B.S. and M.S. degrees in botany from Cornell University. She continued her postgraduate studies in the same subject at Cornell and graduated in 1927. Although as a woman she was not allowed to major in genetics at Cornell, she became the leading member of a small group that was involved in the genetic study of maize at the cellular level. During the 1930s, she held a series of postdoctoral fellowships that allowed her to carry on her research on maize at several prestigious institutions such as the University of Missouri and the California Institute of Technology.

After several more years at Cornell, in 1936, she accepted the position of assistant professor at the University of Missouri at Columbia to work with the influential maize geneticist Lewis Stadler. She resigned from this position after only four years because she felt her career was not progressing. In 1941, she was started Carnegie's Department of Genetics at Cold Spring Harbor in Long Island, New York, on a one-year contract, which turned into a permanent position the following year. McClintock spent the rest of her career at the Carnegie Institution, where she remained an active researcher also after her retirement in 1967. McClintock died at Huntington Hospital, near Cold Spring Harbor, on September 2, 1992.

McClintock devoted her career to the genetics of maize. Focusing on the relationship between plant reproduction and mutations, she discovered important genetic principles, including the physical correlate of genetic crossing-over. McClintock demonstrated how genes moved during the breeding of maize plants and also how physical characteristics depended on certain genes. In spite of the skepticism she encountered from some colleagues, Mc-Clintock's career was marked by important awards and by election in influential scientific institutions. In 1944, she was the third woman to be elected to the National Academy of Science. For her groundbreaking discoveries, McClintock was awarded the National Medal of Science in 1971 and the Albert and Mary Lasker Award 10 years later. She was the first woman to receive an unshared Nobel in the category of Physiology or Medicine and the first recipient of the McArthur Foundation grant [Page 1074]in 1981. She was also the first woman to chair the prestigious Genetics Society of America.