Francis Crick, aged 88, was described last night as an “undisputed genius” and hailed as one of the architects of a new “golden age” of microbiology.
He died at Thornton Hospital, San Diego, California, where he had been battling colon cancer.
Professor Crick shared the Nobel Prize in chemistry in 1962 for discovering the double helix shape of the DNA molecule, one of the crowning scientific achievements of the 20th century.
The prize also went to American Dr James Watson, with whom Prof Crick worked at Cambridge University, and colleague Maurice Wilkins.
Since 1977 Prof Crick had been living in America and working at the Salk Institute in La Jolla, California, pursuing a new goal - to understand the nature of human consciousness.
Identifying the structure of DNA triggered a revolution in biology that is still continuing today. It led directly to the dramatic publication in June 2000 of the entire human genome, containing three billion letters of genetic code.
Science writer Dr Matt Ridley, author of the book Nature Via Nurture, who interviewed Prof Crick last year, said last night: “I personally think he was the undisputed genius of 20th century science, let alone genetics. The sheer power of his imagination and his ability to use logic was remarkable, and led to a series of great discoveries, the most famous of which was the double helix. “He literally reasoned his way to the solution, and he was a 36-year-old mediocrity at the time.” There followed an “extraordinary flow of ideas” from the young chemist.
Prof Crick worked out how DNA was translated into proteins, and how the genetic code was written in sequences of three letters, or codons.
Prof Crick had suffered cancer for a number of years.
Steve Jones, Professor of Genetics at University College London, said: ``There are two major icons of the 20th century; one is the mushroom cloud of the atom bomb, and the other is the double helix.
“In some ways the double helix is the stronger because it is a symbol of hope, not despair. That fact sets Francis Crick apart from just about everyone else.
“I’d say the structure of DNA was the key that opened the lock of the future of human evolution.
“The key to the future is double helix-shaped, and there’s no question but that Francis Crick deserves credit for that.” In a statement from his office at the Cold Spring Harbor Laboratory in New York, Dr Watson paid tribute to his old friend and colleague. “I will always remember Francis for his extraordinarily focused intelligence and for the many ways he showed me kindness and developed my self-confidence.
“He treated me as though I were a member of his family. Being with him for two years in a small room in Cambridge was truly a privilege. I always looked forward to being with him and speaking to him, up until the moment of his death. He will be sorely missed.”