British-born scientist Francis Crick, whose pioneering work helped create the field of modern genetics, has died in California at age 88. The scientist co-discovered the double-helix structure of DNA, the building block of life.

The breakthrough came in 1953, when Francis Crick and a younger American colleague, James Watson, cracked the code of DNA, revealing how cells replicate, and how hereditary traits are transmitted. At the time, they were researchers at Cambridge University. They received the Nobel Prize for Physiology or Medicine in 1962, along with colleague Maurice Wilkins.

Mr. Crick was born in Northampton, England, the son of the owner of a shoe factory. He studied physics, then worked in weapons development for the British navy during the Second World War. He later studied biology and chemistry.

In 1951, the 35-year-old scientist formed a friendship with Watson, a 23-year-old Harvard-trained postdoctoral researcher. Two years later, the pair proposed the double-helix structure of DNA. Their work has made possible the biotechnology industry, genetically modified foods, and new medical techniques like gene therapy.

Mr. Watson, now a researcher in New York, issued a statement praising his late colleague for his "focused intelligence" and "kindness."

Since 1977, Mr. Crick had been a researcher at the Salk Institute in San Diego, where he studied the human brain. Institute president Richard Murphy called him "one of the most brilliant and influential scientists of all time."

Mr. Crick had been battling colon cancer, and died at a medical center in San Diego Wednesday night.