Expressions of near-religious awe and prophesies of dramatic medical advances greeted last week’s announcement that scientists are close to deciphering the human genome, the genetic blueprint for the human body. “Today we are learning the language in which God created life,” President Bill Clinton said at the White House ceremony marking the truce between two groups of scientists racing to complete the genome. “I truly feel this is going to revolutionize medicine because we are going to understand not only what causes disease but what prevents disease,” enthused Dr. Stephen Warren, a U.S. medical geneticist and editor of The American Journal of Human Genetics.
The actual results are bound to be disappointing, except perhaps to the profit margins of pharmaceutical companies and to the grant coffers of researchers. A sober assessment would show that very little can be expected from the genome program that will lead to any health benefits of broad significance in the near future, if ever.
First, there are many technical problems still to be solved. Our current state of knowledge regarding the genetic makeup of human beings may be likened to an incomplete copy of the Concise Oxford English Dictionary as being “the model” from which the plays of William Shakespeare or the novels of Charles Dickens were created. “All” that remains now is to find the prepositions, grammatical rules, and phonetic indications, and then to figure out how the two authors arrived at their story lines, dialogues, and unique literary devices. “The genome is biological programming,” one of the more thoughtful science reporters has written, “but evolution has neglected to provide even the punctuation to show where genes stop and start, let alone any helpful notes as to what each gene is meant to do.”
Second, contrary to the genetic fundamentalism that pervades medical thinking and public awareness these days, genes by themselves cannot possibly account for the complex psychological characteristics, behaviors, or health or illness of human beings. Genes are codes for the synthesis of the proteins that give a particular cell its characteristic structure and functions. They are, as it were, alive and dynamic architectural and mechanical plans. Whether the plan becomes realized depends on far more than the gene itself. Genes exist and function in the context of living organisms. The activities of cells are defined not simply by the genes in their nuclei, but by the needs of the entire organism—and by the interaction of that organism with the environment in which it must survive. Genes are turned on or off by the environment.
Only as small handful of relatively rare illnesses, whether of body or brain, are genetically determined. The most we can say is that some conditions are strongly genetic. Even in the case of well-known single-gene diseases such as Huntington’s, a usually fatal degeneration of the nervous system, there may be protective environmental factors; it is known that of the people who carry the gene a few may, nevertheless, live to a ripe old age without ever developing signs of the disease. In the case of schizophrenia, a mental illness it is currently fashionable to consider genetic, the most that can be shown is that if one member of a pair of identical twins is diagnosed with it, the other will have a fifty or sixty per cent chance of also being similarly diagnosed. And lest people think this proves even a fifty or sixty per cent genetic contribution, it must be remembered that identical twins—even those separated at birth—spend at least nine months in the same formative uterine environment during which time are acted upon by identical biological and psychological influences. So the true genetic effect in schizophrenia is bound to be considerably less than half. The rest is environmental.
For the commonest afflictions of North Americans– heart disease, lung cancer, diabetes–we do not need to seek strong genetic origins. The causes are apparent enough. It has been reported, for example, that among the Cree people of northwestern Ontario diabetes is found at a rate five times the Canadian national average, despite the traditionally low incidence of diabetes among First Nations populations. The genetic makeup of the Cree people cannot have changed in a few generations. The destruction of the Crees’ traditionally physically active ways of life by what we are pleased to call civilization and economic progress, the introduction of high-calorie diets, and greatly increased stress levels are responsible for the alarming rise in diabetes rates.
Among hardcore drug using residents of Vancouver’s Downtown East Side virtually everyone, if asked, can give wrenching histories of childhood abuse or deprivation. Yet at a conference on addiction medicine I attended last year not a single session was granted to social or psychological issues. Time was devoted instead to the genetic bases of substance addictions and alcoholism, as if the environment was not of fundamental importance in both causation and healing.
Given the paucity of evidence for the decisive role of genetic factors in most questions of illness and health, why all the hoopla about the genome project? Science, as all disciplines, has its ideological and political dimensions. The assumption that illnesses, mental or physical, are primarily genetic allows us to avoid many disturbing questions about the nature of the society in which we live. If genes, rather than poverty or made-man toxins or a dysfunction-breeding and stressful social culture are responsible for diseases, we can look to simple pharmacological and biological solutions. Such an approach helps to justify and preserve prevailing social values and structures, and may also be profitable. The value of shares in Celera, the private company participating in the genome project, has gone up 1400 percent from one year ago.
The genome hype is not only poor science, it also suspect as theology. In the Book of Genesis creation story, after all, God fashions the universe first, then nature, and only afterwards shapes humankind from the substance of the earth. He knew, if President Clinton does not, that from their very earliest beginnings humans could never be understood apart from their environment.