The Structure of DNA (Watson, Crick, Franklin, 1953)

Watson and Crick's 1953 paper on the double-helix structure of DNA, built on Rosalind Franklin's X-ray diffraction data, immediately revealed how genetic information is copied via complementary strand unzipping. This single 900-word insight launched molecular biology, enabled genetic engineering, and gave medicine tools to diagnose genetic disease at its root cause. The discovery is arguably the most consequential paper of the 20th century, with the human genome project—a direct descendant—costing $2.7 billion and mapping 3 billion base pairs. It is faster than the average scientific breakthrough in translating to practical applications, with the first genetically engineered drug (human insulin) approved just 29 years later.