Barbara McClintock (1902-92)

Barbara McClintock was an American scientist, distinguished for her research into the structure and functions of chromosomes in plants.

McClintock was born in Connecticut in 1902. She completed her secondary education at Erasmus Hall High School in Brooklyn, before attending Cornell University’s College of Agriculture. Whilst studying botany, McClintock became interested in genetics and was invited to participate in a graduate genetics course at Cornell in 1922. During her time at Cornell, McClintock completed masters and doctoral degrees, conducting extensive cytogenetic research focusing on maize chromosomes. Most significantly she discovered that chromosomes can separate from neighbouring chromosomes and recombine to create unique genetic combinations in a process termed ‘crossing over’.

McClintock later worked at the University of Missouri on the mutagenic effects of X-rays on corn, observing the breakage and fusion of chromosomes in irradiated cells. Her pioneering work on chromosomes continued over the next few years, as she moved from California, to Germany and back to Missouri. In 1942 McClintock joined the Carnegie Institution of Washington at Cold Spring Harbor. Here she made the seminal discovery that genetic elements termed ‘jumping genes’ are capable of moving within the genome and controlling the expression of other genes. Her work in this area represented a significant shift in accepted thinking. Amongst contemporaries her findings were received with confusion, scepticism and, sometimes, hostility. The development of new techniques in the field of microbiology in the 1960s finally confirmed McClintock’s theories.

McClintock received numerous honours and awards during her career. These include membership of the National Academy of Sciences in 1944, the National Medal for Science in 1971 and the Nobel Prize in Physiology or Medicine in 1983.