on-this-day · february 28
the original watson-crick dna molecular model from 1953, now held at the science museum in london. on february 28, 1953, watson and crick walked into the eagle pub in cambridge and announced they had discovered the secret of life. source: wikimedia commons
The Double Helix
On this day in 1953 — Watson and Crick discovered the structure of DNA. The double helix, biology's most elegant design.
2 min read
On February 28, 1953, James Watson and Francis Crick determined the structure of DNA. They walked into the Eagle Pub in Cambridge and Crick announced they had discovered "the secret of life." Watson was 24, Crick 36. They had built a model of deoxyribonucleic acid: two intertwined helical strands held together by paired chemical bases. The double helix.
The critical data came from Rosalind Franklin at King's College London, an expert in X-ray crystallography. In 1952, she produced Photo 51, showing a diffraction pattern characteristic of a helix. Her colleague Maurice Wilkins showed the photo to Watson without her knowledge. Watson recognized its significance immediately.
Using Franklin's data and base-pairing rules from Erwin Chargaff, they built the model: two sugar-phosphate backbones twisted into a helix, with adenine paired to thymine and guanine to cytosine. The structure explained replication. The strands separate, each serving as a template for a new complementary strand. Heredity was a copying mechanism.
a model of the dna double helix according to the watson-crick model — two complementary strands twisted together, with base pairs (adenine-thymine and guanine-cytosine) forming the rungs of the molecular ladder. source: wikimedia commons
They published in Nature on April 25, 1953, in a paper less than a page long. Franklin died of ovarian cancer in 1958 at 37, possibly from X-ray exposure. Watson, Crick, and Wilkins won the Nobel Prize in 1962. Franklin was not included.
The double helix revealed that life is information encoded in four chemical letters, readable, copyable, and editable. Biology became a language on February 28, 1953. We've been learning to read it ever since.