问答题

Don’t Blame DNA　　The really critical implication of the discovery still lies with the door that geneticists have opened on the environmental influences of our behaviour, our personalities and our health, 1 and with the critical blow it strikes on the idea of biological determinism.　　For the past decade, the public has witnessed a rising epidemic of tales of discoveries of genes that dispose humanity to homosexuality, to alcoholism, to political persuasion, to running ability, and to artistic taste.　　But even before yesterday’s revelations by Venter, scientists had stopped believing in the gay gene. Yet belief in its existence still persists among the public. The assault on biological determinism that geneticists have now triggered will be timely, and will prove that human nature is a lot more complex and intriguing than determinists have given it credit for. Even more importantly, the discovery has critical implications for our understanding of idea of free will.　　It has become increasingly fashionable for individuals particularly in the United States to blame actions and crimes on the influence of their genes. Consider the following story. A young American woman, Glenda Sue Caldwell, was convicted of killing her child and was jailed for life. Only later did she begin to display the symptoms of Huntington’s Disease, an inherited brain disorder that produces horrific delusions and uncontrolled movements. Claiming she was a victim of her genes, the woman was cleared on appeal.　　Since then, several other U.S. defendants accused of violent crimes have argued that they too were innocent victims of their genes. They were not responsible for their actions. Their genes were. None of these people have yet succeeded in persuading courts of their innocence and their genes’ guilt. Most lawyers felt such an outcome was nevertheless inevitable. In other words, genetic predestination could soon have been used to excuse murder or robbery—if it had not been for this discovery that we lack the genes to thus dispose us!　　Kevin Davies is the author of The Sequence, a story of the human genome race11. He said, “There has been a recent study on perfect pitch, the ability to know the absolute pitch of a musical note, that strongly suggests that is acquired through the inheritance of a single gene.”　　“That may sound like a clear-cut piece of biological determinism. However, there is a crucial corollary: you have to be exposed to early musical training for the ability to materialize. 13 In other words, even in seemingly simple inherited abilities, nurture has a role to play.”　　And then there is the case quoted by Venter. “Everyone talks about a gene for this and that. But it is not like that. Take the example of colon cancer. People say there is a gene that predisposes us to the disease. And certainly it runs in families. It is caused by an inherited weakness in one gene that controls DNA repair in other genes. 14 But that gene is found in cells in every part of the body. However, it is only the colon where we find all sorts of toxins and bacteria that provide the harsh circumstances that cause that gene to finally break down and for cancer to spread.”　　In short, it is not a colon cancer gene but a gene that affects our ability to respond to the environment. And that, is what human nature is all about.