It's hard to say because the helix existed as a theory before it could be verified. From Wikipedia:

https://en.wikipedia.org/wiki/History_of_molecular_biology#D...

>In 1948, [Linus] Pauling discovered that many proteins included helical (see alpha helix) shapes. Pauling had deduced this structure from X-ray patterns and from attempts to physically model the structures. (Pauling was also later to suggest an incorrect three chain helical DNA structure based on Astbury's data.) Even in the initial diffraction data from DNA by Maurice Wilkins, it was evident that the structure involved helices.

https://en.wikipedia.org/wiki/DNA#History

>Franklin told Crick and Watson that the [phosphate] backbones had to be on the outside. Before then, Linus Pauling, and Watson and Crick, had erroneous models with the chains inside and the bases pointing outwards.

The mere idea of a helix is not especially complex and could have existed in the minds of many theorists at the time. Franklin's discovery provided the final piece of the puzzle, but the desire to attribute major scientific discoveries to a single author or team is based on an incorrect interpretation of the scientific process. The real reason that Franklin didn't win the Nobel Prize is because she died:

>In 1962, after Franklin's death, Watson, Crick, and Wilkins jointly received the Nobel Prize in Physiology or Medicine.[210] Nobel Prizes are awarded only to living recipients. A debate continues about who should receive credit for the discovery.

A student of Franklin, Raymond Gosling, actually took Photo 51. He was not awarded the Prize.