McClintock, Barbara (1902-1992)

US geneticist who discovered jumping genes (genes that can change their position on a chromosome from generation to generation). This would explain how originally identical cells take on specialized functions as skin, muscle, bone, and nerve, and also how evolution could give rise to the multiplicity of species. Nobel prize 1983. McClintock was born in Hartford, Connecticut, and studied at Cornell University, New York. From 1941 she worked at the Carnegie Institute, Cold Spring Harbor, New York. Her research was on the chromosomes of maize. She utilized X-rays to induce chromosomal aberrations and rearrangements and examined the ways in which chromosomes repair such damage. This information from maize plants helped other scientists understand the problems of radiation sickness after the explosion of the atom bomb at Hiroshima, Japan. Further genetic and cytological analysis led McClintock to discover regions of chromosomes that could be transposed from one chromosome to another. These jumping genes acted as regulators and were later discovered in bacteria and in fruit flies.