The unsung hero of science: Barbara McClintock, who won the Nobel Prize in Physiology or Medicine in 1983 for her discovery of mobile genetic elements

In 1983, American plant biologist and cytogeneticist McClintock, one of the great loners of modern­ scien­ce, received the first woman scientist’s unshared Nobel Prize in Physiology or Medicine. Barbara McClintock’s research, conducted in the 1930s, long before the structure of DNA was deciphered, included creating­ the first genetic map of ten chromosomes composing the haploid set of maize microspores and cytological determination of gene location within individual chromosomes. Two phenomena with which Barbara McClintock’s name will forever be associated are crossing over and transposons. Her finding that chromosomes might exchange physical parts as part of gene exchange confirmed Morgan’s theory of inheritance. Experiments in 1940-1950s with the phenotypes of hybrid maize kernels led her to the concept that genetic elements, which she referred to as Dissociation and Activator controling elements, could transpose and regulate the genes by inhibiting or modulating their action. Her revolutionary findings were ahead of their time, in conflict with the established concept of a stable genome and met with scepticism and opposition. Much later, the scientific world accepted her ideas on mobile genetic elements, and it was recognition she appreciated but never sought. McClintock considered the genome as a highly sensitive organ that responds to unexpected events, often by genome restructuring, which scientists today are trying to understand. In this review, the scien­tific path and achievements of Barbara McClintock are analyzed. Keywords: Ac/Ds controlling elements, Barbara McClintock, crossing over, maize genetic map, Nobel Prize, transposons