Jot down ideas
Watson and Crick were not the only one who pored over three-dimensional model of DNA. They were not even the first. On scraps of biochemical data it was possible to build the different molecular shapes, and the options were many.
The conditions of the problem all the same. At the beginning of 1953 it was already clear how to construct the nucleotide:
the phosphoric acid,
one of the nitrogenous bases: adenine (A), guanine (G), thymine (T) or cytosine (C).
Yet it was known that nitrogenous bases scattered around the circuit not by chance in any DNA molecule the total number of adenine and guanine strictly equal to the number of timenow and cytosines. In addition, all x-rays Rosalind Franklin and Raymond Gosling, no matter which part of DNA they were sealed, the thread had the same thickness. This meant that the form remains unchanged under any sequence of nucleotides.
From these introductory Linus Pauling and Robert Corey gathered his model — triple helix, bristling with from all sides of the nitrogenous bases (the sugar and phosphate biochemists took the role of the inner core). It looked precarious and it was not clear why the negatively charged phosphate groups in the center of the spiral do not repel each other.