James D. Watson, whose co-discovery of the twisted-ladder structure of DNA in 1953 helped light the long fuse on a revolution in medicine, crime-fighting, genealogy and ethics, has died, according to his former research lab. He was 97.

The breakthrough – made when the brash, Chicago-born Watson was just 24 – turned him into a hallowed figure in the world of science for decades.

But near the end of his life, he faced condemnation and professional censure for offensive remarks, including saying black people are less intelligent than white people.

Watson shared a 1962 Nobel Prize with Francis Crick and Maurice Wilkins for discovering that deoxyribonucleic acid, or DNA, is a double helix, consisting of two strands that coil around each other to create what resembles a long, gently twisting ladder.

That realisation was a breakthrough. It instantly suggested how hereditary information is stored and how cells duplicate their DNA when they divide. The duplication begins with the two strands of DNA pulling apart like a zip.

Even among non-scientists, the double helix would become an instantly recognised symbol of science, showing up in such places as the work of Salvador Dali and a British postage stamp.