• Sara Thompson

Discovering DNA and Rosalind Franklin

By Sara Thompson

Special to the Enterprise


Woman with short hair looking into a microscope
Rosalind Franklin with a microscope in 1955; Photo by MRC Laboratory of Molecular Biology

DNA carries all the genetic information within all living things, making it one of the building blocks of life. DNA is made up of two polynucleotide strands that wind around each other in a double helix structure. The outer part of the strands are made up of sugars and phosphate groups, and the inner parts are comprised of nucleobases. Several people contributed to the discovery of the double helix structure of DNA, but at the center of it all was Rosalind Franklin.


Franklin was born in London in July of 1920. She was a bright child and excelled in all of her science, math, and language classes, often winning annual awards at school. In 1938, she enrolled at Newnham College, an all women branch of Cambridge. She studied chemistry and in 1941, she was awarded the women’s equivalent of a bachelor’s degree. She would continue working at Newnham as a research assistant in the physical chemistry lab. Here she studied the porosity of coal and its relationship to density. Her research helped to determine the fuel potential of coal and she helped in the development of gas masks during World War II. Her research and contributions led to several published papers and a PhD thesis, which she was awarded in 1945.


After Franklin received her PhD she took a job in Paris doing x-ray diffraction. She was able to use the method to further research coal and how the atoms rearrange themselves when changing phases. Her proficiency in x-ray diffraction helped get her a research fellowship back in London at King’s College. She was put to work using x-ray diffraction of DNA. Along with her assistant, Raymond Gosling, they fine-tuned the diffraction techniques and using a microcamera to take images of the DNA. One of these photographs clearly showed a double helical structure, and she also determined that the outer layers were phosphate groups. Not wanting to publish her data too early, she continued her research on DNA to gather more evidence. Unbeknown to Franklin and Gosling, one of their colleagues shared her data with members of another lab working on a similar project. Using their data and Franklin’s x-ray diffraction images, James Watson and Francis Crick were able to construct a DNA model, showing the double helix structure Franklin has discovered and described a year prior. Their initial publishing did not mention Franklin, but they have since acknowledged her constitutions to their success.


The double helix structure of DNA would likely have been discovered at a later time, but because of Franklin’s expertise and diligence, she was able to discover it in 1952. Rosalind Franklin was sadly diagnosed with cancer in 1956. She continued to research and contribute to science as she underwent treatment, but sadly succumbed to her ailment in April 1958. She is remembered for her contributions to the discovery of the double helix structure of DNA as well as her early work on coal porosity.


 

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