This article by Gareth Huw Davies was first published Radio Times, May 1996.
Dutch scientist Dr Han Brunner was recently approached by a lady terrified of men behaving badly in her family. There seemed to be something "in the blood" and she feared that if she gave birth to a son, he too would grow up a violent, tempestuous chip off the old block. With the menfolk's cooperation Dr Brunner peeled away the machismo and peered into their irreducible genetic essence. He made a startling discovery. One young man was found to have an anomaly in his DNA, the chemical code in the shape of a twisted ladder found in every cell. Just one letter wrong in three thousand million, but that was enough. That mutation changed an enzyme, which altered the chemistry of the brain, which messed up the way the nerves communicate with one other and pushed this man towards the threshold of rage. Had Brunner discovered the "gene for crime"?
Two American attorneys, Charles Taylor and Daniel Summer, certainly thought so. Their client Stephen Mobley is on Death Row in Georgia, convicted of shooting a shopkeeper in the back during a robbery. Taylor and Summer believed they could save Mobley from the electric chair if they could call science in evidence and show that his appalling criminality was gene-driven, that in some way he wasn't altogether responsible for his actions. They even harboured hopes that any inborn defect might be treated and rectified, just as some genetically transmitted diseases like haemophilia and schizophrenia can be treated.
But the case hit a snag. If one son is, literally, a natural born killer, does this brand the rest of the family's menfolk as criminals-in-waiting? Mobley's father did not wait to find out. He sacked the attorneys and, at the time of writing, Mobley is still on Death Row, his genes untested.
Meanwhile, over in Texas the legislature has snatched the "gene for crime" argument for the prosecution. There any killer found with a genetic tendency for murder will be considered beyond redemption, an incorrigible threat to society, and will automatically be sent to the electric chair. Genetics, then, as both Scarlet Pimpernel and state executioner.
Steve Jones, professor of genetics at University College London, a world expert and past Reith lecturer on the subject, met a lot of nasty people in making ???[programme name], from Parkhurst to the ludicrously mis-named Georgia Diagnostic and Classification Centre, where Mobley now resides. But, unlike some of his predecessors, he entered their cells without an agenda.
DNA is found in every cell in your body. It is subdivided into 60,000 genes, which carries the inherited material that distinguishes you. How relevant is it to mitigating outrage, explaining away sin, perhaps even offering a pathway to a medical treatment to prevent crime? Or, as the reformed former criminal John McVicar asserts, do villains turn to crime out of free will? Just don't ask a geneticist to judge, Steve Jones says. The law is on its own.
We are sitting in his third floor office in Wolfson House, just north of the Euston Road in London. Professor Jones, fit, tanned and lithe, with a mellifluous Mid-Wales accent, explains science to the layman better than almost anybody. I find him slumped low in a chair busy on a mobile phone.
He is well aware of the perils of science abused. They permeate the very fabric of this building. Its founder, Victorian psychologist Francis Galton, had great faith in eugenics, which he believed could be used to weed out the insane, the unfit and the criminal. "And we all know where that ended up - Nazi Germany. There's a hell of a long shadow over genetics."
Just as they affect differences in eye colour, height or shape, it is well known that genes also affect behaviour. They influence the parts of the brain controlling hormone production. For example the male sex hormone testosterone makes both mice and men aggressive.
"And now we have genetics and crime. This is a classic case of turning to science to solve social problems, just as people turned in the past to the church - it came up with the idea of original sin, that some people were born imperfect. There's a tendency to say that science can pronounce, and I don't think it can."
This much he will concede. "The science behind the Brunner findings is watertight. There is quite good evidence that the Dutch family's highly anti-social behaviour is associated with a single gene mutation that they carry. I am convinced there are genes that pre-dispose some people towards criminal behaviour." However, it's a long way to the popular press's seductive headline "gene for crime." Then, quite astonishingly, Professor Jones seems to dissent. "Yes, there is a gene for crime. It's the gene that leads the very early embryo, which is nearly always female, into the path of being male. It's the male gene. Almost all criminals are male. That shows what happens if you pursue this argument to its logical conclusion."
We all know crime is inherited. Many children who grow up to be criminals turn out to have had fathers who were criminals. But it doesn't mean crime is encoded into DNA, that a specific propensity to rob, kill, embezzle, rape or mug courses through criminals' veins.
Look at Australia, he says. If there was a gene for crime, Australian blood would be thick with it, passed down from the high proportion of criminals among their founding fathers. Yet, despite the recent tragedy in Tasmania, Australia is an exceptionally calm and ordered society.
Professor Jones shows me a graph with the figures for murders of non-relatives in England and Wales. The line for men rises to a peak at around 24, "when, if they were stags or gorillas, they would be looking for mates and fighting off rivals."
Alongside it is the data for Detroit. The male line rises to the same mountain range of ferocity in the 20s, before falling steeply away. Bingo. Genetics driving crime, and the same in two cities. But I look closer. The Detroit figures are on a massively different scale, a peak of 1100 killings per million people, compared to fewer than 30 per million in Britain.
"The reason the US is a dangerous place has nothing to do with genetics. The UK is the safest place in almost the world in terms of murder because we are a non-violent society with no guns. End of story. So why ask a geneticist?
"The most misunderstood word in genetics is the word `for', as in `a gene for something'. There isn't a gene `for' anything. A gene is just a chemical you can put in a test tube. Genes only manifest their effects in particular combinations and, most importantly, in particular environments. That's the fundamental fact. Once placed in the appropriate social milieu genes do their job. But whereas you can't change easily genes, you can change society tomorrow."
Nevertheless, Professor Jones accepts that genetics will enter the British court room. One day soon a defence lawyer will surely put the case that his client was born to break the rules. And he is confident that the law will cope.
"In the past courts have kept up with scientific advances, such as DNA fingerprinting. If a genetic defence is not based on good science, I would trust the prosecution to shoot it down. The law has always been faced with mitigating circumstances. Genes are just another one."
Phone +44 (0) 1296 668152
Fax +44 (0) 1296 661465
e-mail: 101550.325@compuserve.com
Or write to me at The Old Bakehouse, Chequers Lane, Pitstone Green, Leighton Buzzard, Beds, LU7 9AG, UK.