Decoding the hype
Looking for genetic cures for disease lets us sidestep the need to tackle the social and environmental causes
by Dr. Gabor Maté
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. "This is going to revolutionize medicine," enthused Stephen Warren, a U.S. medical geneticist. "We are going to understand not only what causes disease but what prevents disease."
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 suggests that little can be expected from the genome program that will lead to significant health benefits in the near future, if ever.
First, our current state of knowledge regarding human genetic makeup is like citing an incomplete copy of The Concise Oxford English Dictionary as "the model" from which Shakespeare created his plays. "All" that remains now is to find the prepositions, grammatical rules and phonetic indications, then figure out how Shakespeare arrived at story lines, dialogue and literary devices.
"The genome is biological programming," one thoughtful science reporter 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."
Genes by themselves cannot account for the complex psychological characteristics, behaviour or health of human beings.
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, behaviour 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.
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 a handful of illnesses is 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; of those who carry the gene, a few live to a ripe old age without 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 has a 50 per cent or 60 per cent chance of being similarly diagnosed. Lest people think this proves even a 50 per cent or 60 per cent genetic contribution, it must be remembered that identical twins spend nine months in the same formative uterine environment, and are acted on by identical biological and psychological influences. So the genetic effect in schizophrenia is less than half. The rest is environmental.
For the commonest North American afflictions heart disease, lung cancer, diabetes we don't need to seek genetic origins. The causes are apparent. The northwest Ontario Cree suffer diabetes at a rate five times the Canadian average, despite the traditionally low incidence of diabetes among First Nations populations. The genetic makeup of the Cree hasn't changed in a few generations. The destruction of their physically active way of life by what we call civilization, the introduction of high-calorie diets, 'and increased stress are responsible for the alarming rise in diabetes rates.
Among hard-core drug users in Vancouver's downtown east side, virtually anyone 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, 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 disturbing questions about the nature of the society in which we live. If genes rather than poverty or man-made toxins or a stressful culture are responsible for diseases, we can look to simple pharmacological and biological solutions. This approach helps to justify and preserve prevailing social values and structures. And it's profitable. The value of shares in Celera, the private company participating in the genome project, has risen 1,400 per cent in a year.
In Genesis, God fashions the universe first, then nature, and only afterward shapes humankind from the substance of Earth. God knew, if Mr. Clinton does not, that from their earliest beginnings humans could never be understood apart from their environment.
Gabor Maté, a Vancouver physician, is the author of Scattered Minds: A New Look at the Origins and Healing of Attention Deficit Disorder.