The Watson-Crick Model of DNA
(1953)
Deoxyribonucleic Acid (DNA) is a double-stranded,
helical
molecule. It consists of two sugar-phosphate backbones on the outside, held
together by hydrogen bonds between pairs of nitrogenous bases on the
inside. The bases are of four types (A, C, G,
& T): pairing always occurs between A & T, and C & G. James Watson (1928 - ) and
Francis Crick (1916 - 2004) realized that these pairing rules
meant that either strand contained all the information necessary to
make a new copy of the entire molecule, and that the order of
bases might provide a "genetic code".
Watson and
Crick shared the Nobel
Prize in 1962 for their discovery, along with
Maurice Wilkins (1916 - 2004),
who had produced a large body of crystallographic data
supporting the mode. Working in the same lab, Rosalind Franklin (1920 -
1958) had earlier produced the first clear crystallographic
evidence for a helical structure. Crick went on to do
fundamental work in molecular biology and neurobiology. Watson
become Director of the Cold Spring Harbor Laboratory, and
headed up the Human Genome
Project in the 1990s.