by Margaret Dedloff
Barbara McClintock was a geneticist who studied the genetics of maize, also known as corn (Figure 1). She made several important discoveries, but one finding in particular won her the Nobel Prize in Physiology or Medicine in 1983. In the 1940s and 1950s, McClintock discovered mobile genetic elements, also termed transposable elements, or jumping genes. Mobile genetic elements are sections of our DNA that are able to move around to different places in the genome (Figure 2). The discovery of mobile genetic elements changed the field of genetics and how scientists view the genome.
Figure 1. An image of maize, the type of corn that Barbara McClintock studied. Image source
Figure 2. A diagram demonstrating how mobile genetic elements are able to “jump” from one area in the genome to another. Image source
In June of 1902 Barbara McClintock was born in Hartford, Connecticut. At the time, no one knew that her future work would change the entire field of genetics. Her father was a doctor and likely inspired Barbara’s interest in science from a young age. She was a bright child and finished high school a year early. McClintock wanted to continue her education, but her mother was worried that if she went to college it would be hard for her to find a husband. McClintock’s father was supportive of her goals and she was able to enroll in Cornell College of Agriculture in 1919. McClintock took a genetics course and immediately knew that was what she wanted to study. She received her bachelor’s degree in 1923, a master’s degree in 1925, and a PhD in 1927. McClintock began studying maize during graduate school and used a special technique that allowed her to visualize each individual chromosome present in the corn she was studying.
Following the completion of her graduate degree, Barbara McClintock had several different researcher and instructor positions. One of the challenges that McClintock faced was that many places would not want to hire or fund a woman. Finally, Barbara McClintock began a job as an assistant professor at the University of Missouri, but chose to leave the position in 1941, so she could focus only on research and not teaching. McClintock moved to the Cold Spring Harbor Laboratory in New York, an important biomedical research site (Figure 3). It was there that she discovered mobile genetic elements. She noticed that maize kernels had varying coloring, and when studying these different pigments she found that there were two genes that moved around the chromosome. When these genes would move, the pigment in the kernels would be different.
Figure 3. Barbara McClintock at the bench at Cold Spring Harbor Laboratory. Image source
While Barbara McClintock’s findings with maize were interesting, they were largely ignored by the wider scientific community, until 1983 when she was awarded the Nobel Prize in Physiology or Medicine. McClintock persisted in her research despite disbelief of her results and gender bias of people in the field, and to this day she remains the only woman to be the sole awardee of the Nobel Prize in Physiology or Medicine.
