Key reflections

The 50th anniversary of the publication of the proposed double-helix structure for DNA by James Watson and Francis Crick last year was widely celebrated. But historically, we are still perhaps too close to the event to realise its ultimate significance. Therefore, the more people who were involved or who subsequently worked with the molecule write and tell of their experiences, the richer history will eventually be. A new book, based on a series of lectures given last year at Darwin College, Cambridge, edited by Torsten Krude, provides much valuable information. Darwin published his theory to account for the extraordinary variety of species found on this planet almost exactly 100 years before Crick and Watson announced the structure of chromosomal DNA. The theory of natural selection provoked immediate and passionate debate and caused outrage in some sections of society. By contrast, knowledge of the structure of DNA has already led to many developments in research, agriculture and medicine, and has widespread practical uses, whereas it is only now that the social effects are becoming important. In view of the wide range of techniques now available for the detection and manipulation of DNA and the number of uses to which they are put, it is clear that eight essays can provide only a glimpse into their chosen subjects. Inevitably there are aspects that are not discussed. In this context, it is surprising that there is no essay on methods of sequencing or on the value of the genomic sequences. Current projects to describe the entire genome of different species depend on being able to determine the sequence of nucleotides in a fragment of DNA. Fred Sanger, working in Cambridge, devised the method that is still in use today and for which he was awarded his second Nobel prize in 1980. Within a mere 15 years, an international collaboration obtained the first Feature