In honor of Women’s History Month, it is fitting to pay tribute to the woman who is
considered one of the greatest biologists of the twentieth century! Barbara McClintock (1902–1992) was an American scientist and cytogeneticist who focused on color mosaicism in maize, or corn, during the 1940s. She was awarded the Nobel Prize in Physiology or Medicine in 1983 for her groundbreaking work describing the ability of DNA to move between locations within the genome (she is the only woman to receive an unshared Nobel Prize in that category).
She created the first genetic map for corn and also discovered transposons—mobile genetic elements that tend to move (or “jump”) between locations in the genome. Her work with corn introduced the scientific world to some radical new ideas has had a significant impact on our modern-day understanding of genetics, and paved the way for our understanding of the genome!
McClintock’s work with corn demonstrated that transposable elements in our DNA could naturally be broken and moved. For much of the 20th century, scientists believed an organism’s DNA was permanently fixed in its order and only changed through isolated mutations. While not every segment of DNA can “jump,” many regions can, and because of her work, scientists have since found almost half of the human genome is made up of these transposable elements!
Barbara McClintock also introduced the thought that jumping genes could affect the activity and function of other genes. She found a gene could potentially jump into the middle of another gene, causing it to function differently. This helped scientists better understand human genetics, including helping to discover how diseases, such as hemophilia, develop. Think of your DNA as a recipe book. Now imagine you took a sentence from a car repair manual and pasted it into the middle of a lasagna recipe. If you followed the new recipe step by step, your lasagna likely wouldn’t come out right.
McClintock was the first woman to be president of the Genetics Society of America, the third woman to be elected to the National Academy of Sciences, and the third woman to win the Nobel prize in Physiology or Medicine. She embodied the idea that science should have no boundaries—if you are curious, then you can be a scientist!
Your students can explore DNA with these fantastic hands-on RAFT ideas:
By Jeanne Lazzarini, RAFT Math Master Educator/Curriculum Writerx