When the double helix structure of DNA was discovered, scientists claimed that they had unravelled the secret of life itself. The crucial piece of evidence was provided by the expert crystallographer Rosalind Franklin – the famous photograph 51, an X-ray picture showing a dark cross of dots, the signature image of a concealed molecular spiral.
The life-changing innovations that followed – mapping the human genome, test-tube babies, genetic engineering – all depend on understanding the chemical foundations of heredity.
