Legend: Barbara McClintock (1902-1992)
The BioTalk Magazine
“If you know you’re on the right track, if you have this inner knowledge, then nobody can turn you off..no matter what they say,” were the words of the Nobel laureate Eleanor McClintock, known to the world as Barbara McClintock. Ironically, for a scientist who was ahead of her time, she was awarded the prestigious Nobel prize in Physiology or Medicine in 1983, 30 years after her “discovery of mobile genetic elements”. Her revolutionary research challenged the basic concepts of genetics and proved that genetic elements are dynamic and sometimes change position on a chromosome, causing genes to alter their function.
Born in Connecticut in 1902, Barbara moved to Brooklyn, NY with her family in 1908 where she finished her schooling. She was a talented student who almost would have missed college for getting married. Though her mother rejected the idea of enrolling in college thinking it would harm her chances of marriage, Barbara with the support of her father completed her B.S. in Agriculture (1919-1923, Plant breeding & Botany), M.S. in Botany (1923-1925) and PhD in Cytology (1925-1927, Genetics) from the Cornell University and dedicated her life to research, choosing never to get married.
During her undergraduate studies at Cornell, while most students interested in agriculture opted for plant breeding as a major subject, Barbara was more interested in a relatively new and revolutionary discipline- genetics. Sensing her intense interest in the subject, a professor in the Department of Plant Breeding, Dr. Hutchinson invited her to join the only course in genetics offered to graduate students at Cornell. She also took a course in cytology offered by Lester W. Sharp of the Department of Botany, who studied the structure of chromosomes and their behaviors at mitosis and meiosis. These courses had an immense impression on Barbara’s mind to the extent that she decided to pursue her further studies in the upcoming field of cytogenetics- the study of chromosomes and their genetic expression. To that end, Barbara conducted cytological investigations of the cereals during her masters’ degree and studied triploid corn plant and the meiotic behavior of chromosomes for her PhD degree.
She advanced the understanding of chromosomes and traits linked to them by developing ways to visualize them microscopically. She was the first to describe genetic recombination by crossing-over during meiosis and produced the first genetic map for maize, linking regions of the chromosome to physical traits. She also unraveled the role of the telomere and centromere in chromosomes through her cytogenetic studies.
Despite her excellence in research, it was difficult for her to find a job during the Great Depression. She eventually joined as an assistant professor at the University of Missouri in 1936 but left in 1941 to focus and pursue research full-time at the Cold Spring Harbor Laboratory, and stayed until retirement. It was here that she began her studies on the mosaic color pattern of maize at the genetic level. She observed that the kernel patterns were too unstable to be caused by mutations and changed frequently over generations. Her research indicated that the only way this was possible in successive generations of the plant was if some genetic elements moved around or “transposed” within chromosomes and disrupted the function of genes. These findings went completely against the current understanding of genetics and were rejected by most of her peers. During a lecture at the Annual Symposium in 1951, her theories perplexed the audience, and they thought she was crazy. Sensing her work was incomprehensible to common wisdom, she stopped publishing and lecturing about her work. She stuck to her theory and never stopped the research, despite being criticized by many scientists. Finally, in the mid-1960s, with the advances made in molecular biology, her findings were validated by the scientific community and eventually she was honored with the prestigious Nobel prize in 1983. Till date she remains the only woman to receive an unshared Nobel prize for her work.
During her lifetime Barbara McClintock was honored with several awards, honorary doctorates, medals, honorary memberships, commemorative postage stamp and even a street named after her. She continued her role as a key leader and researcher in the field at Cold Spring Harbor Laboratory even during her last years. On September 2, 1992, at the age of 90, Barbara died of natural causes leaving behind her legacy of invaluable contribution to science and humanity.