Erwin Chargaff (1905-2002)

Chargaff discovered the pairing rules of DNA letters, noticing that A matches to T and C to G. He later criticized molecular biology, the discipline he helped invent, as "the practice of biochemistry without a licence", and once described Francis Crick as looking like "a faded racing tout".

Francis Crick (1916- )

Crick trained and worked as a physicist, but switched to biology after the Second World War. After co-discovering the structure of DNA, he went on to crack the genetic code that translates DNA into protein. He now studies consciousness at California's Salk Institute.

Rosalind Franklin (1920-58)

Franklin, trained as a chemist, was expert in deducing the structure of molecules by firing X-rays through them. Her images of DNA - disclosed without her knowledge - put Watson and Crick on the track towards the right structure. She went on to do pioneering work on the structures of viruses.

Linus Pauling (1901-94)

The titan of twentieth-century chemistry. Pauling led the way in working out the structure of big biological molecules, and Watson and Crick saw him as their main competitor. In early 1953, working without the benefit of X-ray pictures, he published a paper suggesting that DNA was a triple helix.

James Watson (1928- )

Watson went to university in Chicago aged 15, and teamed up with Crick in Cambridge in late 1951. After solving the double helix, he went on to work on viruses and RNA, another genetic information carrier. He also helped launch the human genome project, and is president of Cold Spring Harbor Laboratory in New York.

Maurice Wilkins (1916- )

Like Crick, New Zealand-born Wilkins trained as a physicist, and was involved with the Manhattan project to build the nuclear bomb. Wilkins worked on X-ray crystallography of DNA with Franklin at King's College London, although their relationship was strained. He helped to verify Watson and Crick's model, and shared the 1962 Nobel with them.