Signer's Gift – Rudolf Signer and DNA

Abstract

In early May 1950, Bern chemistry professor Rudolf Signer traveled to a meeting of the Faraday Society in London with a few grams of DNA to report on his success in the isolation of nucleic acids from calf thymus glands. After the meeting, he distributed his DNA samples to interested parties amongst those present. One of the recipients was Maurice Wilkins, who worked intensively with nucleic acids at King's College in London. The outstanding quality of Signer's DNA – unique at that time – enabled Maurice Wilkins' colleague Rosalind Franklin to make the famous X-ray fiber diagrams that were a decisive pre-requisite for the discovery of the DNA double helix by James Watson and Francis Crick in the year 1953. Rudolf Signer, however, had already measured the physical characteristics of native DNA in the late thirties. In an oft-quoted work which he published in Nature in 1938, he described the thymonucleic acid as a long, thread-like molecule with a molecular weight of 500,000 to 1,000,000, in which the base rings lie in planes perpendicular to the long axis of the molecule. Signer's achievements and contributions to DNA research have, however, been forgotten even in Switzerland.