Francis Crick, who with James Watson deciphered the double-helix structure of DNA in 1953 using Rosalind Franklin's X-ray data, died of colon cancer in La Jolla, California. His discovery, one of the twentieth century's most consequential, launched the field of molecular biology and later earned him a Nobel Prize shared with Watson and Maurice Wilkins in 1962.
Crick had abandoned a physics career after World War II, drawn instead to what he called the borderline between the living and the non-living. Working at Cambridge's Cavendish Laboratory with the brash young American James Watson, he built wire-and-metal models late into the night, chasing the shape that would explain how genetic information could be copied and passed on.
The breakthrough, a double helix with base pairs A-T and G-C linking two intertwined strands, relied heavily on X-ray diffraction images produced by Rosalind Franklin, whose contribution went largely uncredited for decades, a controversy that still shadows the discovery's legacy. Watson and Crick announced their model in a famously terse one-page paper in Nature in April 1953, ending with the dry understatement that the structure had 'not escaped our notice' that it might explain heredity.
Crick spent his later decades at the Salk Institute pursuing an even more elusive target: the neural basis of consciousness. He worked until nearly his last day, reportedly editing a paper on the claustrum from his hospital bed, chasing what he called the 'astonishing hypothesis' that the mind is nothing but the behavior of neurons.