Rosalind Franklin's notes reveal she understood DNA double helix

A new analysis of Rosalind Franklin’s laboratory notebooks challenges the long-standing historical narrative regarding her role in discovering the DNA double helix. For decades, the prevailing account—largely popularized by James Watson—suggested that while Franklin produced critical X-ray diffraction images, she failed to fully grasp their structural implications.

However, research published in the Journal of the History of Biology indicates that Franklin had indeed identified the helical nature of DNA. Her notes reveal that she recognized the pattern in earlier images, such as Photograph 49, and had calculated key dimensions, including the 3.4 nanometer pitch of the helix. The study suggests she was actively interpreting her data and approaching the same conclusions as Watson, Crick, and Wilkins, rather than being a mere provider of experimental data.

Franklin died in 1958 at the age of 37, four years before Watson, Crick, and Wilkins were awarded the Nobel Prize in Medicine. This new evidence provides a corrective to a history that has frequently minimized her intellectual contributions to the discovery.