Crick and Watson decipher the DNA

James D. Watson

James D. Watson (*April 6, 1928)

On February 28, 1953,  American molecular biologist James D. Watson and English biophysicist Francis Crick announced to friends that they succeeded to determine the chemical structure of DNA.

Already in the 19th century biochemists were able to isolate DNA and RNA from the cell nuclei mixed together. They later found out that DNA and RNA had to be distinct from each other. The nuclein was identified by Friedrich Miescher in 1869 and he later on isolated the pure DNA from a salmon’s sperm. The term ‘nucleic acid’ was then coined by Richard Altmann and it was only found in the chromosomes. The Lithuanian-American biochemist Phoebus Levene at Rockefeller Institute made further achievements concerning the DNA’s structure, showing that its components, the sugar and phosphate chain were linked in the order phosphate-sugar-base. Each of these was named nucleotide and the scientist assumed that the DNA molecule consisted of a string of nucleotide units, which were linked together through phosphate groups. In his understanding however, the chain was short and its bases repeated in a fixed order, the theory that the DNA was a polymer was later suggested by Torbjorn Caspersson and Einar Hammersten.

Francis Crick (1916 – 2004)

Francis Crick (1916 – 2004)

Further efforts on the DNA’s structure were made in the 1950’s, and three known groups worked on the topic. Rosalind Franklin and Maurice Wilkins [6] of King’s College London belonged to the first group, Francis Crick and James Watson from Cambridge formed the second group and Linus Pauling and his team at Caltech depicted the third. Crick and Watson were able to build physical models of metal rods and balls, incorporating the chemical structured of the nucleotides. In the late 1940’s, Pauling and his team discovered many proteins included helical shapes and also Wilkins found out that in the DNA’s structure, helix’ were somehow involved. Watson and Crick then began answering questions like whether the bases pointed toward the helical axis or away or what the angles and coordinated of all atoms and bonds were.

Due to an inspiration by Erwin Chargaff, Watson and Crick used X-ray diffraction and added several data by Rosalind Franklin,[5] which resulted in the accurate model of the DNA’s molecular structure. The extraordinary discovery was announced on February 28, 1953 and the news spread quickly. A new milestone was set in molecular biology.

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  • Rosalind Franklins ground breaking work was given by Wilkins to the pair and undoubtedly provided the impetus for their “discovery”. She was never awarded her true recognition as she died from ovarian cancer and was therefore ineligible for her duly deserved noble prize share (no posthumous recognition). The recipients have never been courteous nor grateful enough to acknowledge her vital contribution playing to their own sense of historical importance and downplaying the true influence of her ground breaking findings. Pity this article doesn’t either.

  • Writer lmb is correct. While you do mention the “slight” in your nice tribute to Franklin (2014), your readers should know that Franklin was supposed to attend a meeting where all the principles had gathered but was on vacation. The crucial image was shown, without her permission, and as you point out, the final idea quickly became apparent! Within about 48 hours, Watson and Crick (at a pub) had penned the famous 1953 Nature paper with only a passing mention to Franklin in the acknowledgments. She was robbed! In the 9th ed of Exercise physiology. Energy, Nutrition and Human Performance (; authors McArdle, Katch, Katch), in a chapter dealing with molecular biology and its history, we pay tribute to Franklin and further state, “. . . these revelations reveal a seldom seen but ugly side of some in the basic sciences—cutthroat ways and blind ambition run roughshod over other researchers’ contributions without proper attribution.” Highly recommend this book for insides about Franklin’s contributions: Sayre, Anne (1987) [1975]. Rosalind Franklin and DNA. New York: W.W. Norton & Company, Inc. ISBN 0-393-32044-8.


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