Pioneers in discovering the structure of DNA

The secret of transmission of hereditary characteristics in the helical chemical structure of DNA

In March 1953, two young men, Francis Crick and James Watson, surprised the world by successfully creating a correct model showing the chemical structure of DNA in a Cambridge University laboratory, ahead of many chemists, biophysicists, biologists and geneticists around the world. Their success did not come from a vacuum, as it had a long, complex and convoluted history of hard work, joint collaboration, disappointments, happy coincidences and fierce competition between scientists. Their success culminated in the 1962 Nobel Prize winner in Physiology or Medicine, Maurice Wilkins, a friend of theirs at Imperial College.

Francis Crick

Francis Harry Compton Crick (1916-2004) was born in a small village near the English city of Northampton. His father was a shoemaker, but young Francis loved science from a young age. He won a school prize in chemistry at the age of seventeen, and received a BA in physics from the University of London in 1937.

Crick began preparing for a PhD in physics at the University of London to study the viscosity of water at high temperatures, and he found the study boring, so he was very pleased when a bomb fell on his laboratory and destroyed its equipment. World War II, so he went on to participate in the design of sea mines at that time.

After the war, he returned to studying biology and developing the science of biophysics, like many physicists of the time. He wrote about this change in his interests. “I had to move from the study of physics in its elegance and profound simplicity to the study of the detailed and subtle mechanisms of biochemistry, which had evolved over billions of years. It’s like being born again.” However, Crick felt that his study of physics encouraged him to be more daring than biologists in introducing new ideas, perhaps because of the impressive scientific achievements that physics provides in understanding the world and the universe.

Crick tried to join his friend Wilkins at the Imperial College Laboratories, but was rejected by its director, Sir John Randall, so he joined the Cambridge University Laboratories under Sir Lawrence Bragg. Sir Bragg won the Nobel Prize in Physics in 1915 for his study of X-ray diffraction imaging of crystals, and was only twenty-five at the time. In the late 1940s, Sir Bragg was in fierce competition with the famous American scientist Pauling to arrive at the structure of proteins, and Pauling had preceded him by describing the helical shape of some proteins in 1951.

Bragg also competed with the team of Sir Randall, Director of the Biophysics Laboratories at Imperial College, to find the structure of DNA. Crick was first assigned to study the structure of protein molecules by X-ray diffraction imaging, and during this period he experienced the feelings of frustration and failure that prevailed in his Cambridge University laboratory when Pauling preceded them in learning about the helical shape. proteins. He learned a lot from looking at mistakes in protein modeling, and he benefited greatly from all these experiments when he turned his attention to discovering the structure of DNA.

James Watson

As for his colleague James Dewey Watson (1928), he was born in Chicago, America, he was a brilliant and meritorious student, so he was able to enter the University of Chicago when he was only fifteen years old and received a scholarship. . His interest turned to the study of genetics after reading the famous physicist Schrödinger’s book What is Life. He received the scientific degree in zoology in 1947.

He then earned his PhD at Indiana University, where he studied under the American geneticist Hermann Joseph Muller (1890-1967), who was awarded the Nobel Prize in Physiology or Medicine in 1946 for his research on the phenomenon. genetic abnormalities caused by radiation exposure. He also studied there under the Italian-American microbiologist Salvador Edward Luria (1912-1991), who also received the Nobel Prize in Physiology or Medicine in 1969 for his research on virus replication and genetic structure.

In 1951-1952, Watson moved to several laboratories at various universities in America, Copenhagen, and Italy, where he continued his research on viruses, proteins, and nucleic acids. His interest in studying the structure of nucleic acids using X-ray diffraction imaging techniques grew after he heard Wilkins lecture at a conference in Italy in 1951, during which he presented his images.

His teacher Luria helped him get a scholarship to work in Cambridge University laboratories to learn these imaging and research methods, and so Watson came to Sir Bragg’s lab to study the use of X-ray diffraction imaging to learn about composition. hemoglobin and one of the muscle proteins, myoglobin. They didn’t have enough offices, so he ended up sharing with Francis Crick. A coincidence that had historical results. When they met in Cambridge, Watson was twenty-three and Crick thirty-five.

Watson and Crick at Cambridge University in 1952


Dr. Amer Sheikhoni’s book “The History of Heritage as Discovered by Its People”.

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