Tim Radford | Jan 12, 2003 | 7 min read
The DNA revolution may be just too big to take in: beyond words, even 50 years on. Think of four chemical bases coupled exclusively to each other, adenine with thymine, guanine with cytosine, in a double helix. Then think of this double helix having the power to unwind and duplicate, to make new helixes. So far, so simple. The structure spells out a gene that makes a protein, and makes more DNA. But like the double helix itself, the challenges divide into questions of scale and complexity. In