Limitless Promise, Limited Delivery By John Horgan
NEW YORK — Early last week, a Scottish biologist named Ian Wilmut announced that he had extracted DNA from an adult ewe, inserted the DNA into the ovum of another sheep and induced the ovum to grow to term in the womb of a third animal. The first successful cloning of a mammal has triggered a frenzy of fretting by scientists, ethicists and other learned types about scientists “playing God.†No less a sage than George Stephanopoulos intoned: “What this creates is the possibility of immortality.â€
But before we start conferring divine powers upon ourselves, we should put this claim in perspective. Wilmut tried to clone DNA from 277 sheep in all--and only one took. Until his feat is replicated, some experts caution, no one can be sure his technique really works. And even if sheep can be reliably cloned, the technique may not work in humans because of peculiarities of our embryonic development.
Still, let’s assume that cloning humans turns out to be feasible. Given how few people are likely to take advantage of what would probably be a difficult and expensive procedure, it does not seem to merit so much hyperventilation. Many commentators simply find the notion of genetically matched humans to be extremely creepy. The millions of identical twins living around the world must be getting a little annoyed by now.
In the midst of all the hype over the cloning of Dolly, we may need a reminder of just how far we are from achieving truly Godlike mastery of our own flesh. By focusing almost exclusively on the advances of science, the media have credited science with much more power than it really has. Science has made little or no headway in crucial areas of research, and some of its reputed advances have proved to be illusory.
Take behavioral genetics, which seeks the genetic basis for various complex human traits and disorders. Over the past decade or so, the media have served up story after story proclaiming the discovery of genes “for†schizophrenia, manic depression, alcoholism, novelty-seeking and homosexuality.
These reports, like the case of the cloned lamb, inspired heated debates about what we will do with such knowledge. The homosexuality findings generated the most lurid speculation. Would a right-wing administration test people for homosexuality and exclude them from government service? Would straight couples abort fetuses with the “gay gene� Would gay couples eliminate straight fetuses?
But these concerns may be moot, given that follow-up studies by other scientists have failed to corroborate the initial claims about gay genes. In fact, none of the claims involving genes for complex traits have, so far, held up to the scrutiny of other researchers. Unfortunately, the negative results, unlike the initial claims, are usually buried in the back pages of newspapers, if they are covered at all. So the public is left with a false impression of inexorable scientific progress.
To be sure, genuine progress has been made in finding genes associated with certain diseases, such as Huntington’s chorea, cystic fibrosis, Lou Gehrig’s disease and early-onset breast cancer. Tests are now available for identifying those who carry these genes and thus are likely or certain to contract the associated disease. But none of the promises of therapies based on this genetic knowledge have been fulfilled.
Cancer research poses a similar paradox. Since President Richard M. Nixon officially declared a “war on cancer†in 1971, the United States has spent some $30 billion on research. Scientists have taken enormous strides toward understanding how different types of cancer occur, and they have invented sophisticated methods for detecting the disease and tracking its course.
But mortality rates from cancer have remained, overall, virtually unchanged during that period--and, in fact, for the 50 or so years for which reliable data exist. All the research on cancer since 1971 has had a disproportionately minuscule impact on treatment. Basically, physicians still cut cancer out with surgery, poison it with chemotherapy or burn it with radiation. Maybe, someday, all our research will yield a “cure†that will render cancer as obsolete as polio and smallpox. Maybe not. Maybe cancer is simply too complex a problem to solve.
Science has also made pitifully little progress at understanding our fantastically complicated and often troubled minds. To be sure, researchers have acquired powerful tools for probing the brain, with microelectrodes, magnetic resonance imaging and positron-emission tomography. But all this work has failed to yield either a powerful new theory of the mind or truly effective treatments for its assorted disorders.
In his 1993 best-seller “Listening to Prozac,†the psychiatrist Peter Kramer portrayed us as marching inexorably toward an era in which we can fine-tune our moods and personalities with designer drugs. Kramer loftily ruminated over whether the elimination of depression, anxiety and other common afflictions might also extinguish something central to our humanity.
But Kramer’s brave new world is a fantasy. He builds his case for Prozac on anecdotes, but large-scale studies show that Prozac and other so-called wonder drugs are no more effective for treating common emotional disorders than the more primitive antidepressants, which themselves are no more effective, statistically speaking, than talk therapy. Prozac, touted for its supposedly minimal side effects, actually causes impotence and other sexual disorders in most users--a fact that Kramer relegated to a footnote.
Kramer was on firmer ground when he said, at the end of his book, that our understanding of our own minds is still “laughably primitive.†The question is, when, if ever, will that situation change? In spite of all the claims about the “death of Freud,†some therapists still practice psychoanalysis, which Sigmund Freud invented a century ago. And why not? No treatment for the mind has been proved to be superior to psychoanalysis. Cheaper, maybe, but that is not a scientific criterion.
The hot, up-and-coming treatment for severe depression, and even schizophrenia and other intractable disorders, is electroshock therapy, which can cause severe memory loss and other side effects. Is that a sign of progress?
The ultimate achievement for applied biology, of course, would be immortality. Former presidential advisor Stephanopoulos apparently thinks that cloning will help us attain that goal. But, for most citizens, I suspect, immortality means something more than making a younger genetic copy of yourself. As Woody Allen once said, “I don’t want to live forever through my work. I want to live forever by not dying.â€
The possibility that scientists can identify and then learn how to arrest the mechanisms underlying senescence is a perennial favorite of science writers. An article in the New Yorker last fall reported on the belief of some biologists that telomeres, clumps of DNA that cap the ends of chromosomes, might be the key to vastly extended life spans. Telomeres tend to shrink over time, and some scientists have speculated that they might be able to forestall the aging process by preventing telomeres from shrinking.
The New Yorker writer dutifully pondered whether immortality--like cloning or tests for gay genes--is really a good thing or not. But it turns out that telomeres may not really play such a crucial role in aging after all, according to recent experiments. Blaming shortened telomeres for senescence, one researcher remarked, is like blaming wrinkles.
Moreover, the eminent evolutionary biologist George Williams, among others, has suggested that immortality may be impossible to achieve. Natural selection designed us to live long enough to breed and raise our children. As a result, senescence almost certainly does not stem from any single cause or even a suite of causes; it is woven inextricably into the fabric of our being.
Lurking beneath all the hysterical talk about the precipitous pace of science, I suspect, is more than a little wishful thinking. Science has extended and enriched our lives in many ways, intellectually and materially. It has given us vaccines and birth-control pills and jets and laptop computers. But we still cannot comprehend ourselves. We still get cancer and become depressed. We still grow old and die. Far from becoming Godlike, we are as mortal as ever.*
