British-born scientist Francis Crick, who helped discover the double helix shape of DNA along with James Watson, has died aged 88.
Professor Crick, who was battling colon cancer, died at Thornton Hospital in San Diego, US.
He won the Nobel Prize for his work on DNA's structure, which he studied in 1953 at Cambridge University.
"I will always remember Francis for his extraordinarily focused intelligence," the BBC quoted Professor Watson as saying on Thursday.
"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," Prof Watson said. "I always looked forward to being with him and speaking to him, up until the moment of his death. He will be sorely missed."