In their 1953 letter, James Watson and Francis Crick announced the most important scientific discovery of the second half of the 20th century. They had discovered the structure of DNA: the molecule of inheritance, the chemical messenger which carries the genetic information parents pass on to their children. As Watson and Crick found, it has the structure of a double helix.
Society today is only just beginning to understand the consequences of that discovery, made in a dingy laboratory in Cambridge 41 years ago. One consequence is in the Criminal Justice Bill: if it becomes law, a sample of DNA will be extracted from everyone convicted of a serious criminal offence. That DNA will be analysed, recorded and filed. The state will have begun to compile a genetic database on its citizens.
The detection of crime is one of two applications of genetics that interest governments. In a country such as Britain, with its National Health Service, the state also has an interest in genetic medicine. The two applications form an interesting contrast. For when it comes to crime and punishment, the state has enthusiastically taken up genetic technology, brushing aside dangers to individual liberty. But the response to medical applications, which promise to ameliorate real human suffering, has been less enthusiastic.
NHS reforms have created an 'internal market' in which district health authorities have to buy treatment for people in their areas and, naturally, seek the cheapest form of treatment so as to reduce costs.
Unfortunately, even though genetic and congenital disease accounts for about half of all childhood deaths in Britain, each individual condition is comparatively rare, and it is not worthwhile for a health authority to fund the genetics laboratory, counsellors and other trained specialist staff required to deliver proper genetic medicine. For the moment some services are provided on a 'pooled' regional basis, but the support groups and the families affected by genetic disease are looking to the future with anxiety.
It would be a bitter irony if, after all the money spent on laboratory research, the new structures of the NHS denied patients the fruits of that research. Yet that is a real prospect.
To its credit, the Department of Health has taken the initiative in reorganising treatment for at least one set of genetic diseases: the inherited disorders of the red blood cells known as thalassaemia and sickle-cell anaemia. Sickle-cell disease predominantly afflicts people of Afro-Caribbean ancestry, while thalassaemia is prevalent among people from Asia and eastern Mediterranean areas such as Greece, Turkey and Cyprus.
One effect of sickle-cell disease is that rigid red blood cells clog up smaller blood vessels, causing agonising, deep-seated pain. There are between 5,000 and 6,000 sufferers in Britain, predominantly young and black - and they are not getting the treatment they need. When a young black man appears in an inner-city casualty department writhing in pain, shouting and demanding pethidine or diamorphine, some doctors think they are dealing with a drug addict. They keep the patient lying there, denying him the pain relief he knows he needs, sometimes for more than a hour.
The Department of Health is belatedly setting up an identity card system for sickle-cell sufferers, so that they can get the treatment they need instantly. But the department has not found more money, nor a way to make regional genetics facilities secure.
Contrast the enthusiasm with which genetics is being harnessed to the pursuit of crime. In 1991 a House of Commons committee recommended that every man in Britain should be genetically fingerprinted. The assumption was presumably that all men are potential rapists and so their DNA should be on file, accessible to the police.
This astonishing proposal was taken up by the Royal Commission on Criminal Justice, which last year recommended sweeping powers for the police to take samples for DNA analysis, with or without the suspect's consent - whether or not DNA evidence was relevant to the crime. These proposals have been incorporated into the Criminal Justice Bill.
According to Home Office figures, up to 500,000 DNA samples could be fed into a database each year. Even if less than one-hundredth this number were subjected to DNA analysis, Britain would still be carrying out the world's most intrusive and repressive DNA surveillance programme on its citizens. Yet serious sexual assaults and murders for which DNA evidence is currently used account for less than 6 per cent of the annual total.
In contrast to this massive criminal database, one of the most extensive medical screening programmes in the country - for cystic fibrosis at the Royal Manchester Children's Hospital - has tested the DNA of only 1,500 people since 1989.
There are reasons for believing that, technically, the DNA database scheme will be expensive, unsound, and will lead to miscarriages of justice. But ultimately the fear must be that if we concede this first step towards the state holding genetic information on its citizens, the journey will end only when all of us have our genetic profiles on the Government's database.
The technique can be used to establish paternity, so why shouldn't the Child Support Agency take DNA samples to ensure that errant fathers pay proper maintenance? In some countries, France for example, the state requires couples contemplating marriage to take blood tests, apparently to check that neither partner carries venereal disease and so to prevent the disease being passed on to children. Logic would dictate that intending couples should have genetic profiling as well. The lifetime cost to the NHS of treating someone with cystic fibrosis is about pounds 200,000, so universal genetic testing could reduce the economic burden of inherited disease.
There were many paths from that Cambridge laboratory 41 years ago: is this one really the direction in which society wishes to go?
This is an edited version of a talk to be given at the Wellcome Centre for Medical Science in London on Wednesday at a meeting chaired by Professor James Watson.
Tom Wilkie's book 'Perilous Knowledge', a study of the implications of modern genetics, is published by Faber and Faber at pounds 14.99.Reuse content