£2 coin to mark 50 years since DNA discovery

The Royal Mint is to issue a £2 coin inscribed with the DNA double helix to mark the 50th anniversary of one of the most important scientific discoveries of the 20th century.

The celebrations will include a formal banquet in London, with Tony Blair as guest of honour, and the unveiling of a blue plaque on The Eagle pub in Cambridge where two young scientists dreamt up their vision of the double helix over pints of beer.

James Watson and Francis Crick are perhaps the best-known double act in science. While working at Cambridge University's Cavendish Laboratory, round the corner from The Eagle, they published a seminal scientific paper in the journal Nature on 25 April 1953, entitled A Structure for Deoxyribonucleic Acid.

They suggested the DNA molecule consisted of two entwined strands, wrapped around each other to form a double helix. With classic understatement they wrote that the structure has novel features of "some considerable biological interest".

Watson and Crick postulated that each helix was linked to the other by a system of paired bonds between four chemical compounds, represented by the letters G, C, T and A, which all appear on the £2 coin. They suggested that G pairs with C, and T with A. Again with considerable understatement they ended their paper with the sentence: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material."

By unravelling the structure of DNA, Watson and Crick helped to decode the mystery of inheritance. The double helix led to a fundamental understanding of how genes worked and, just as important, how they were copied and passed on from one generation to the next. They shared the Nobel prize with Maurice Wilkins of King's College London, whose work with Rosalind Franklin on X-ray diffraction helped the Cambridge pair to determine the DNA structure. Dr Franklin died three years before the prize was awarded.

Fifty years on from the discovery it is difficult to find an area of biology, medicine, anthropology or criminology that has not seen alteration or development generated by that seminal finding.

Professor Watson, who is president of Cold Spring Harbor Laboratory in New York, plans to come to Britain to attend the celebrations in London and Cambridge this April, but Professor Crick, 86, is thought to be too frail to make the journey from his home near San Diego, California.

The focus of the 50th anniversary celebrations will be on the Medical Research Council's Laboratory of Molecular Biology (LMB) in Cambridge, built 10 years after the double-helix discovery to capitalise on Britain's lead in what was then a new field. The LMB can claim more Nobel prizes than any other British institution, the most recent being the 2002 medicine prize won by John Sulston, Sydney Brenner and Robert Horvitz, for their work on the genetics of the nematode worm.