British scientist who, with James Watson, solved the structure of DNA in February 1953. One of the 20th century's greatest biologists, he was as famous for his bold theorising as for his discoveries.
In February 1953, after five weeks of intense work, Crick and Watson determined the double-helix structure of DNA at Cambridge. Their success depended in part on X-ray data from King's College London, taken by Rosalind Franklin and Maurice Wilkins, which they used without permission. In the structure Crick deduced how DNA replicated itself and concluded that the sequence of bases was the source of genetic information. In 1962 Crick, Watson and Wilkins shared the Nobel prize in medicine. Franklin had died in 1958.
Crick proposed the mechanism by which DNA was translated into protein and helped crack the genetic code. He contributed to the understanding of collagen's structure, devised prescient theories of embryonic development and later turned his attention to the neural basis of consciousness. He moved to the Salk Institute in San Diego, where the neuroscientist Christof Koch became his sparring partner.
Crick came to science late, completing his PhD at 37. He preferred theory to experiments, leaving fiddly lab work to others, and did very little teaching or administration. Most of his best ideas came from conversations with peers—Watson and then Sydney Brenner in Cambridge, Koch in San Diego. Colleagues reported hearing him constantly "prattle away in his loud voice".
He was unafraid of being wrong. Before settling on the double helix he proposed a triple one. He published an incorrect structure of collagen and a mistaken theory about the genetic code. In one paper he argued that life on Earth began from microbes sent by extraterrestrial beings. He called this approach his "don't worry method": a theory should not be rejected merely because some evidence failed to fit, since data could be flawed and measurements could be wrong.
Crick was competitive—sometimes unscrupulously so—and unafraid of offending others. His lectures were famous for their energy and scope; his research papers are still admired for their clarity. He had an interest in eugenics. His personal life was colourful, replete with parties, affairs, drugs and feuds.
A biography by Matthew Cobb, a zoologist at the University of Manchester, "Crick: A Mind in Motion" (Basic Books/Profile Books, 608 pages), was published in 2025.
He who hesitates is last.