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| Top Level > Sciences & Technology > Life Science |
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Facts |
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Cracking the code
The secret of the DNA code of life was finally unravelled at Cambridge University, England in 1953 by an American, James Watson, then 25, and a 37 year old biologist, Francis Crick. They knew that DNA consisted of a chain of sugars and phosphates held together by four components know as nucleotides. Each nucleotide contained a different organic base. There were two large bases, guanine and adenine, and two small ones, thymine and cytosine. But how did the bases fit together?
Biking from the railroad station to the college one day after a trip to London, Watson decided to experiment with a two-link structure. He and Crick made cutout models of the shapes of the four molecule bases and began trying to fit them together.
Watson recorded their moment of triumph. "Suddenly I became aware of that an adenine-thymine pair...was identical in shape to a guanine-cytosine pair." The bases linked in pairs, each pair forming a single run in the DNA ladder, and each base determined what it's partner could be. The two sides of the spiral ladder fell into place. |
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