Watson, James Dewey (1928– )

US biologist who was awarded a Nobel Prize for Physiology or Medicine in 1962 for the discovery of the double-helical structure of DNA and determining the significance of this structure in the replication and transfer of genetic information. He shared the prize with his co-worker Francis Crick.

Crick and Watson published their work on the proposed structure of DNA in 1953, and explained how genetic information could be coded.

Watson was born in Chicago and studied there and at Indiana. He initially specialized in viruses but shifted to molecular biology and in 1951 he went to the Cavendish Laboratory at Cambridge, England, where he performed the work on DNA with Crick. In 1953 Watson returned to the USA. He became professor at Harvard in 1961 and director of the Cold Spring Harbor Laboratory of Quantitative Biology in 1968, and was head of the US government's Human Genome Project 1989–92.

Crick and Watson envisaged DNA replication occurring by a parting of the two strands of the double helix, each organic base thus exposed linking with a nucleotide (from the free nucleotides within a cell) bearing the complementary base. Thus two complete DNA molecules would eventually be formed by this step-by-step linking of nucleotides, with each of the new DNA molecules comprising one strand from the original DNA and one new strand.