DNA: The Watson Crick Double Helix Model

The model I reconstructed was based on this photograph. I had recovered enough base-pairs from the original (identified for some by the writing in Crick’s hand). Maurice sent my pictures to Crick to verify. He agreed that the writing could be his and that the base pairs were from the models used at the Cavendish. Crick never objected to the model being reconstructed but he was certainly not enthusiastic about it.

original watson crick model
Original Watson Crick double helix model of DNA
source: photo given to author by MHF Wlikins

I was introduced to Herman Watson by Maurice Wilkins when Watson was visiting King’s Biophuysics laboratory in Drury Lane. Herman Watson had been told by Maurice about my interviewing Linus Pauling about his scientific discoveries and activism against atmospheric nuclear weapons testing. Professor Watson mentioned to me that when he had moved to Bristol University from the Cavendish Labs a large number of wooden tea chests full of disassembled molecular models were sent to him. He seemed fairly certain that he’d seen DNA base pairs in this collection.

We made arrangements for me to travel to Bristol to take a look. There were quite a few tea chests stored in different labs but Professor Watson had identified most of the ones of interest. I took most of the day going through each tea chest and their were indeed a large number of base pairs that resembled those used in the original model. However, there were no components to make up the sugar-phosphate chains. I recovered a little more than would be needed to reconstruct a model from the original Watson Crick double helix model photograph and Professor Watson also wanted to keep the remainder. As John Kendrew’s doctoral student Professor Watson had been the minder of these relics partly because Kendrew was the designer of a large number of molecular model components at the Cavendish. Max Perutz also constructed extraordinarily beautiful models of haemoglobin.

John Kendrew (left) and Max Perutz in front of a molecular model of haemoglobin

Made of soldered tin plate and wire the bases were recognised as similar to those used in the original Watson Crick model. Francis Crick noted that he wrote on a number of model components and the original model to his recollection had been disassembled and it’s pieces were not known to have been kept together.

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