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How did Rosalind Franklin’s X-ray diffraction images contribute to understanding DNA?

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Diagram of a DNA double helix showing its twisted ladder structure, with a close-up of the sugar-phosphate backbone, paired nitrogenous bases (adenine, thymine, cytosine, guanine), and labeled nucleotides and hydrogen bonds. — human genome The human genome is made up of approximately three billion base pairs of deoxyribonucleic acid (DNA). The bases of DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).

Rosalind Franklin’s X-ray diffraction research was instrumental in deciphering the molecular structure of DNA. By producing clearer X-ray patterns of DNA molecules, she was able to determine the density of the molecule and, crucially, establish that it existed in a helical conformation.12

Her high-quality images and data provided the essential evidence that allowed James Watson and Francis Crick to propose in 1953 that DNA is a double-helix polymer—a structure consisting of two strands wound around each other. While Maurice Wilkins also conducted vital X-ray diffraction studies on DNA at King’s College, Franklin’s specific contributions in capturing these structural patterns laid the foundational insights necessary for the discovery of the double-helix model.123