Franklin was so unhappy at Kings that she had determined to move her research elsewhere. Wilkins, who worked at Kings College with Franklin, was having some personality conflicts with her. Both men officially turned to other research but privately continued to think about the DNA problem. Embarrassed by this public failure, the director of the Cavendish lab told Watson and Crick to abandon their model-building efforts.

She pointed out that, when her research was applied correctly, the nitrogen bases belonged on the inside of the molecular structure. Her research results had plainly shown there were two forms of DNA, the wetter B form was clearly what Watson and Crick were trying to model, but they were trying to build the structure without the moisture she had shown was present. When they unveiled the model to colleagues, Franklin was scathing in her criticism. Watson and Crick built a three-stranded helix with the nitrogen bases on the outside of the structure. There is no way we can stick in a regular sequence of bases in the center in a regular fashion.’”Īs a result of Watson’s mistake, the men’s first attempt at building a DNA model was a notable failure. … I had heard her talk wrong and I thought there was very little water in it (DNA) and therefore it should be a very compact structure … We said ‘Well, there are four types of bases. He apparently did not pay close attention.

About this time, Watson attended a lecture given by Rosalind Franklin at nearby Kings College. A visiting graduate student pointed out that new information, not yet corrected in the text books, showed that Watson was using one of his cardboard chemical bonds backwards. Neither man had a degree in chemistry, so they used standard chemistry texts to cut out cardboard models of chemical bonding configurations. Watson and Crick had difficulty with their first attempts to build a DNA model. The men understood that discovering the structure of the DNA molecule would be a major scientific breakthrough, and they knew they were in competition with other scientists, such as Linus Pauling, who were also working on DNA. Both were convinced that understanding the molecular geometry would be central to discovering how DNA could transmit genetic information from parent to daughter cells. Watson and Crick decided to use a model-building approach to try to discern the molecular structure of the DNA molecule.

The Double Helix by James D. Watson