With Franklin and Gosling gathering additional ​​evidence, and Crick and Watson concentrating on generating new ​​hypotheses, the puzzle of DNA seemed close to being solved. But a personal conflict would soon change the course of this discovery. From the time that Franklin started working in the lab, she and Wilkins had argued about which of them would get to work on DNA. Initially, their boss had asked Wilkins to hand the project over to Franklin — so Wilkins gave her all of the high-quality DNA ​​sample. Later, he decided he wanted to keep working on the problem anyway, but Franklin had already gotten started and didn’t want to be pushed out. The resulting tension made both of them unhappy, and shortly after image B 51 was taken, Franklin notified her boss that she wanted to leave the lab. This left Gosling, her student, upset and without a Ph.D. supervisor. He decided to seek advice from Wilkins — and when he did, he took a critical piece of evidence with him: image B 51.

Wilkins had always been more interested in DNA B anyway, and he took special notice of the clear, informative image. Later that month, Watson came to London for another lab colloquium. After the talk, Wilkins had dinner with Watson and showed him the beautiful image of DNA B produced by Franklin. Because Crick had helped Watson learn how to interpret the X-ray patterns produced by helices, Watson immediately recognized the tell-tale evidence of a helix — which he had suspected all along — as well as other clues that would help Watson and Crick put all the puzzle pieces together. Determined not to make the same mistake as before, Watson asked Wilkins for more details, and this time, he wrote everything down.