1. Experimental Data:
* X-ray Diffraction Images: These were crucial. Rosalind Franklin and Maurice Wilkins produced high-quality X-ray diffraction images of DNA fibers. These images revealed the helical structure of DNA, its dimensions, and the repeating pattern of its structure.
* Chargaff's Rules: Erwin Chargaff had discovered that in DNA, the amount of adenine (A) always equals the amount of thymine (T), and the amount of guanine (G) always equals the amount of cytosine (C). This was vital for Watson and Crick to understand the base pairing within DNA.
* Chemical Analysis: Previous research had determined the chemical components of DNA – deoxyribose sugar, phosphate groups, and the four nitrogenous bases (A, T, G, C).
2. Existing Knowledge:
* Linus Pauling's Work: Pauling had previously determined the alpha-helix structure of proteins, which provided valuable insights into the potential helical nature of other molecules.
* Previous Models: There were already models of DNA proposed, but they were incorrect. These failures provided valuable lessons for Watson and Crick.
* General Principles: Watson and Crick used their knowledge of chemistry, physics, and biology to understand how the various components of DNA could interact to form a stable structure.
Here's a description of the data in a more concise way:
Watson and Crick used a combination of experimental data (X-ray diffraction images, Chargaff's rules, and chemical analysis) and existing knowledge (previous models, Pauling's work, and general principles) to decipher the structure of DNA. It was this combination that allowed them to build their iconic double-helix model.
It's important to remember that while Watson and Crick received the Nobel Prize for their discovery, they were not the only ones involved. The contributions of Rosalind Franklin, Maurice Wilkins, Erwin Chargaff, and Linus Pauling were crucial in the quest to understand the structure of DNA.
