Cambridge’s Second Darwin
Francis Crick earned his PhD at Caius College in the University of Cambridge, but only after being rejected from the University for failing its Latin requirement, having his studies interrupted by the Second World War, and completing his revolutionary research with James Watson (who was twelve years younger and already had his PhD). Needless to say, the doctorate was long overdue!
Francis Crick is mostly famous for his discovery of DNA’s structure. He and his colleague James Watson studied the X-ray diffraction image known as “Photo 51” to conclude that DNA had a double-helix structure stabilized by covalent bonds. In 1953, the two biologists published their model of DNA, which eventually earned them the Nobel Prize in Physiology or Medicine in 1963.
Crick’s Discovery: Under the Microscope
A popular misconception about Crick and Watson’s findings is that they discovered DNA’s double-helix shape all by themselves. In fact, much of the scientific community understood that this macro-molecule looked like a twisting ladder; the question was how did it stay that way? Crick and Watson noticed that each strand of DNA had special molecule known as a nucleotide, which had four varieties of bases: Adenine (A), Guanine (G), Thymine (T), and Cytosine (C). The key to the DNA model was that these four bases made two pairs of covalent bonds: Adenine bonds with Thymine, and Guanine bonds with Cytosine. These bonds are what make up the “steps” on DNA’s twisted ladder shape, and it is the reason how such a massive molecule can stay in one piece!
So now that the shape of DNA was solid and confirmed, the next question was how it divided. If DNA is the “blueprint molecule” for all proteins, how does it replicate and avoid running out? There were three theories: one stated that DNA copied itself as a whole without any cutting required (conservative theory), another claimed that DNA cut horizontally at the “steps” and filled in the gaps with new material (dispersive theory), and a third suggested that DNA split straight down the middle and built new DNA from the two original halves (semi-conservative theory). Crick and Watson were the major advocates for the semi-conservative theory, and in the end it was accepted that DNA replicated by “unzipping” itself to create new copies.
Francis Crick’s Legacy
Crick wrote four books on topics like microbiology, genetics, the origin of life, and spirituality’s role in a scientific world. The Royal Society honors this revolutionary scientist through the Francis Crick Medal and Lecture, an annual award designed for younger biologists (under 40) to promote new findings and ideas. The Francis Crick Institute in London is currently the largest bio-medical research center in Europe. The University of Cambridge celebrates its late champion of biology through the Francis Crick graduate lectures hosted by the Graduate School of Biological, Medical, and Veterinary Sciences.
Even though the University of Cambridge originally rejected Crick, time and determination proved the young microbiologist to be the University’s second Darwin.
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