Who really discovered DNA’s structure?

Tuesday 28 February marks the 70th anniversary of – in my view – the most important day in the history of science. On a fine Saturday morning with crocuses in flower along the Backs in Cambridge, two men saw something surprising and beautiful. The double helix structure of DNA instantly revealed why living things were different: a molecule carries self-copying messages from the past to the future, bearing instructions written in a four-letter alphabet about how to synthesise living bodies from food. In the Eagle pub that lunchtime, Francis Crick and James Watson announced to startled fellow drinkers that they had discovered the secret of life.

That all living creatures, from microbes to ministers, turn out to share the same universal genetic cipher is why this breakthrough was more momentous as well as more unexpected than any other discovery I can think of. (Newton’s gravity? Just another force. Columbus’s America? Just another continent. Darwin’s evolution? Close. Mendel’s genetics? Not as big as DNA. Einstein’s relativity? Too obscure. Heisenberg’s and Schrodinger’s quantum mechanics? Too hard to understand. Fibonacci’s double-entry book-keeping? Nice try.)

The American James Watson is now the sole survivor of the five main actors and their many colleagues whose work led to that moment. Alas, at 94 he has lived in seclusion since a car accident three years ago left him with significant memory loss. I called him this week for a chat but he no longer recalls much about the events of 70 years ago. His tendency to shock people with provocative remarks, which maybe worked when he was the enfant terrible of science in the 1960s and the head of the Human Genome Project in the 1990s, and which enabled him to write the painfully honest bestseller The Double Helix, had tarnished his reputation in the years before the accident.