Have you ever wondered why your hair is curly like your mother’s, or you have freckles like your father? Or maybe your parents say you smile like your uncle, who you don’t even see that much. All these things are related to your genes. Genes are the stuff inside your body that tell your cells how to build YOU. You get your genes from your mom and dad, and they got them from their parents. Genes are made out of a substance called DNA, which is short for deoxyribonucleic acid. Don’t worry, you don’t have to remember that!
But, you might also wonder, what exactly does DNA look like?
Rosalind Franklin wondered about that question too, and as a scientist, she helped answer it. It wasn’t an easy question to answer, because DNA is much, much too small for people to see. Knowing how DNA is put together would help other scientists learn more about how it works, and eventually make all kinds of other medical advances possible. And Franklin did end up discovering what DNA looks like!
But before we get to that, we need to go back to London, in 1920, where Rosalind Franklin was born. Franklin was part of a well-off Jewish family, who had been involved in politics for a long time. One uncle served in the British government. Another uncle and aunt were activists for women’s voting rights, which Britain granted in 1918. Her mother did charity work, and her father was a banker and a teacher. During World War II, the Franklin family took in Jewish refugee children who had escaped from Europe.
Rosalind’s obsession wasn’t politics though. She did care about people, but she was fascinated by science. As a child, Rosalind’s aunt described her as “alarmingly clever–she spends all her time doing arithmetic for pleasure, and invariably gets her sums right.” Rosalind didn’t really spend every moment of her childhood doing math. She was good at most other subjects too. She learned German, French and Latin, but did not do well in music! Even though she was an excellent student, she also enjoyed sports, travel, and hiking. But by the time Rosalind was a teenager, she knew that she wanted to be a scientist. She realized that this, too, could be a way to help people.
When it was time to go to college, Rosalind won a scholarship to pay for it. Since she didn’t really need it, she decided to donate her scholarship to a deserving refugee student. Because of World War II, many people were trying to escape Europe. Many came to England, and did not have much when they arrived. A scholarship to go to college would have been a huge gift.
Franklin studied chemistry at Newnham College, a women’s college that is part of Cambridge University. After she finished her studies, she worked in a lab at Cambridge, but didn’t feel she was respected there. Also, World War II was still raging, and Franklin hoped to do something to support the war effort. So, she left Cambridge to work at the British Coal Utilization Research Association. Studying coal might sound very boring, but it was actually very important work. Coal was critical to the war effort because it was used in gas masks that soldiers wore. These masks filtered out harmful gasses and particles that might otherwise make them sick. Rosalind made several discoveries that helped improve gas masks.
After the war, a friend helped Franklin get a job in a lab in France. Rosalind loved France – the language, the food, and the people. In her new job, she learned to use X-Ray crystallography, which allows scientists to take pictures of microscopic structures, things far too small to be seen with your eyes, and even too small for most microscopes. She became an expert in using this technology, and it would help in her later work on DNA.
In 1950, a professor named John Randall asked Franklin to build an X-ray crystallography lab at the King’s College in order to study DNA. However, Dr. Randall didn’t inform Maurice Wilkins, a scientist who had also been working on DNA at King’s College, that he had hired Rosalind to be in charge of the lab. This upset Wilkins, who thought he would be in charge. The two did not get off to a good start, and never really got along.
Even so, Franklin launched into her work in the lab with the help of an assistant named Raymond Gosling. She improved the X-ray camera, which allowed her to take much clearer images of microscopic structures. This would allow her and Gosling to make their big breakthrough.
But before we get much further, we need to go back a little and talk about what DNA is and why scientists were so excited about it in the 1950s.
DNA is the instructions for building you. Not just you, but any plant, animal, or other living thing. You are made of billions of cells that are too tiny to see with your eyes. There are many types of cells, but each one contains a copy of all your DNA.
Think of each cell in your body as a Lego set. You have lots of pieces that can be used to make different parts of your body. Your cells also have machinery for building those blocks into the parts of your body, like fingernails, muscles, or eyes. DNA is like the instruction booklet: it tells your cellular machinery which blocks to use and how to put them together to make the different parts of your body.
People knew DNA existed before the 1950s. They’d known about it for almost 100 years, and knew something about the chemicals it was made of. But they didn’t know the details of how those chemical pieces were put together. Remember, the pieces that makeup DNA are WAY too small for anyone to see with their eyes, or even with the microscopes that existed at the time.
One more important discovery about DNA came just a few years before Franklin began working on it. Remember when we talked about genes in the beginning of the episode?
They’re how parents pass traits–like brown hair, big feet, or freckles–on to their children. In 1944, a scientist named Oswald Avery first showed that DNA is what makes up genes. Before that, no one was sure what was inside living things that did this. He showed that DNA was that thing, which made people very eager to learn more about it!
So by the 1950s, several scientists were trying to figure out exactly how DNA was put together. Using her upgraded X-Ray crystallography camera, Franklin and Gosling took a photo of DNA. Taking this photo wasn’t like snapping a picture on your cell phone. It took hours of work and careful planning. Franklin called it Photo 51, and it was the key to understanding how DNA is put together. Photo 51 looks like a circle with an X made of little dashes in the middle.
But this wasn’t the end of Franklin’s work. Remember, a photo shows something only from one angle. This was going to be kind of like trying to figure out what a building looks like by looking at a picture of its roof. Franklin got to work using the photo and her knowledge of the chemistry of DNA to try to figure out what the whole structure was put together. In a few months, she had worked out that DNA was shaped like a double helix. To imagine what a double helix looks like, picture a rope ladder. You’re holding the ropes on one end and a friend holds the other end. If you twist the ropes on your end, you’ll get a double helix!
Unfortunately, Franklin wouldn’t be the one to show the world what DNA looked like. Maurice Wilkins got a hold of Photo 51 and showed it to his friend James Watson. Pretty soon, Watson and his coworker Francis Crick were using the photo to try to figure out DNA’s structure. They also worked out that it was a double helix. Watson and Crick wrote a paper and quickly published it, just weeks before Rosalind Franklin had planned to publish her own paper.
Franklin didn’t realize that Watson had seen her photo, so she thought they had done all the work and made the discovery on their own. She had also started a new job, and was glad to be out of the tense environment at King’s College. At her new lab, she and her coworkers made important discoveries about a virus that affects plants, called tobacco mosaic virus. Franklin was glad to feel appreciated and respected again.
Rosalind Franklin would never know that her photograph had helped Watson and Crick decipher the structure of DNA. Unfortunately, she passed away of cancer only a few years later. Watson and Crick would go on to win a Nobel Prize for learning the structure of DNA. It’s unfair that Franklin didn’t get the credit she deserved while she was alive, but strangely enough, it was James Watson who eventually revealed her role in the discovery of the double helix, in a book he wrote in 1968.
Even though she didn’t get credit for her DNA discovery while she was alive, Rosalind Franklin knew she had made important contributions to science. She felt that science was the best way not only to explain life, but to improve the world. She knew that her work on coal, x-ray crystallography, and plant viruses had done this, so she was proud of her work. In the end, Franklin was more concerned with learning and improving lives with science than she was with being first to do something. She spent her life trying to answer important questions, and even though it’s a little late, people do celebrate that now. I hope you pass along what you’ve learned about Rosalind Franklin, so more people can celebrate her achievements!
Berger, Doreen. “A Biography of the Dark Lady of Notting Hill.” The United Synagogue, Dec. 3, 2014. https://www.theus.org.uk/article/biography-dark-lady-notting-hill
Borgert-Spaniol, Megan (2018) Rosalind Franklin: unlocking DNA. Abdo Publishing, Minneapolis.
Maddox, Brenda. “The double helix and the ‘wronged heroine.’” Nature 421, 407–408 (2003). https://doi.org/10.1038/nature01399
Pray, Leslie A. (2008) “Discovery of DNA Structure and Function: Watson and Crick.” Nature Education 1(1):100. https://www.nature.com/scitable/topicpage/discovery-of-dna-structure-and-function-watson-397/
Oswald Avery. Wikipedia. https://en.wikipedia.org/wiki/Oswald_Avery
Rosalind Franklin. Wikipedia. https://en.wikipedia.org/wiki/Rosalind_Franklin