Crick, Francis Harry Compton

▪ 2005

      British biologist (b. June 8, 1916, Northampton, Eng.—d. July 28, 2004, San Diego, Calif.), together with American biologist James D. Watson, in 1953 made what was widely considered the most momentous discovery in modern biology: the double-helix structure of large molecules of DNA. Crick and Watson were endeavouring to understand the molecular nature of genetic material when they discovered DNA's structure. They quickly determined how the double-helix structure gives DNA unique properties for retaining and replicating the genetic information of living things. For their discoveries Crick and Watson, along with New Zealand-born British biophysicist Maurice Wilkins (q.v. (Wilkins, Maurice Hugh Frederick )), were awarded the Nobel Prize for Physiology or Medicine in 1962. Crick went on to play a major role in advancing knowledge in the field of molecular biology. Among other accomplishments, he showed how the sequence of molecular subunits along a strand of DNA in a cell carries information designating the structure of proteins needed for the cell's life functions. In the late 1970s Crick turned away from molecular biology in order to study problems in neurobiology, in particular the biological basis for consciousness. The Astonishing Hypothesis: The Scientific Search for the Soul (1994) presented his view that all manifestations of the soul can essentially be reduced to the activity of the brain. Crick studied physics at University College, London (B.Sc., 1937). During World War II he served as a physicist under the British Admiralty, but after the war he decided to pursue studies in biology. He joined the University of Cambridge's Strangeways Research Laboratory in 1947, and in 1949 he transferred to the Medical Research Council Unit at the university's Cavendish Laboratories. Crick received his doctorate from Cambridge in 1954. In 1977 he left Britain for the Salk Institute in San Diego, where he held the position of distinguished professor and served (1994–95) as president. Crick was made (1959) a fellow of the Royal Society for his work on DNA, proteins, and viruses; he received the Order of Merit in 1991. What Mad Pursuit: A Personal View of Scientific Discovery was published in 1988.

* * *

▪ British biophysicist

born June 8, 1916, Northampton, Northamptonshire, England

died July 28, 2004, San Diego, California, U.S.

 British biophysicist, who, with James Watson (Watson, James Dewey) and Maurice Wilkins (Wilkins, Maurice), received the 1962 Nobel Prize for Physiology or Medicine for their determination of the molecular structure of deoxyribonucleic acid (DNA) (DNA), the chemical substance ultimately responsible for hereditary control of life functions. This accomplishment became a cornerstone of genetics and was widely regarded as one of the most important discoveries of 20th-century biology.

 During World War II, Crick interrupted his education to work as a physicist in the development of magnetic mines for use in naval warfare, but afterward he turned to biology at the Strangeways Research Laboratory, University of Cambridge (1947). Interested in pioneering efforts to determine the three-dimensional structures of large molecules found in living organisms, he transferred to the university's Medical Research Council Unit at the Cavendish Laboratories in 1949.

      In 1951, when the American biologist James Watson arrived at the laboratory, it was known that the mysterious nucleic acids, especially DNA, played a central role in the hereditary determination of the structure and function of each cell. Watson convinced Crick that knowledge of DNA's three-dimensional structure would make its hereditary (genetics) role apparent. Using the X-ray diffraction studies of DNA done by Wilkins and X-ray diffraction pictures produced by Rosalind Franklin (Franklin, Rosalind), Watson and Crick were able to construct a molecular model consistent with the known physical and chemical properties of DNA. The model consisted of two intertwined helical (spiral) strands of sugar-phosphate, bridged horizontally by flat organic bases. Watson and Crick theorized that if the strands were separated, each would serve as a template (pattern) for the formation, from small molecules in the cell, of a new sister strand identical to its former partner. This copying process explained replication of the gene and, eventually, the chromosome, known to occur in dividing cells. Their model also indicated that the sequence of bases along the DNA molecule spells some kind of code (genetic code) “read” by a cellular mechanism that translates it into the specific proteins responsible for a cell's particular structure and function.

      By 1961 Crick had evidence to show that each group of three bases (a codon) on a single DNA strand designates the position of a specific amino acid on the backbone of a protein molecule. He also helped to determine which codons code for each of the 20 amino acids normally found in protein and thus helped clarify the way in which the cell eventually uses the DNA “message” to build proteins. From 1977 until his death, Crick held the position of distinguished professor at the Salk Institute for Biological Studies in San Diego, California, where he conducted research on the neurological basis of consciousness. His book Of Molecules and Men (1966) discusses the implications of the revolution in molecular biology. What Mad Pursuit: A Personal View of Scientific Discovery was published in 1988. In 1991 Crick received the Order of Merit.

* * *