The Genetic Revolution—Great Promise With Growing Concern
THE genetic revolution is moving out of the laboratory and into everyday life. Has it already affected you? Consider:
▲ Genetically altered bacteria can now produce in abundance such valuable drugs as insulin, human growth hormone, and a vaccine for hepatitis B.
▲ Clinical trials have begun in the United States on two potential vaccines against AIDS, both created with genetics.
▲ Prenatal testing for numerous inherited diseases is becoming possible, as “markers” for those diseases are found in human DNA. A highly sensitive and very rapid prenatal test for sickle-cell anemia has been introduced.
▲ The actual genes that cause certain hereditary diseases have been pinpointed and, in some cases, reproduced by cloning through genetic engineering.
▲ Flushed with success in finding genes, some scientists are pushing the idea of a genetic “Manhattan Project” to determine the precise coding of all the 100,000 or so genes on the 23 pairs of chromosomes that make up human DNA. The U.S. federal government agreed to support the project. If approved by Congress, it is expected to take 15 years and cost several billion dollars.
▲ In 1987 the U.S. patent office said that it was ready to consider applications for patents on animals that had been altered by genetic engineering technology, setting off a lively debate among scientists and ethicists. In April 1988 such a patent was granted for a mouse.
Large-Scale Drug Production
Perhaps the most immediate payoff of gene-splicing is in the area of drug production. Sales of genetically engineered drugs are expected to exceed a billion dollars per year in the near future. But this success has not come overnight.
Take insulin, for example. One of the early practical results of recombinant-DNA technology was to track down the gene (located on chromosome 11) for human insulin and then splice copies of it into ordinary E. coli bacteria. These altered bacteria can produce large quantities of insulin with the exact structure of the human insulin molecule. Amazing!
It took several years, however, for this technology to move out of the laboratory, through clinical trials, past the U.S. FDA drug approval process, and finally into full-scale production and wide availability. The availability of this insulin does not mean that a cure for diabetes has been found, as any diabetic will tell you. In fact, while the product “may have certain advantages for people newly treated with insulin or allergic to the usual beef/pork insulin [it] is not necessary for the majority of people taking the conventional preparations,” according to Dr. Christopher D. Saudek, director of the Johns Hopkins Diabetes Center.
Other hot prospects for genetically engineered drugs include TPA (tissue plasminogen activator) and IL-2 (interleukin-2). TPA helps to dissolve blood clots. It has been approved by the FDA for emergency treatment of heart-attack victims. IL-2 belongs to a family of factors that act primarily between white blood cells. It promotes the growth and development of T cells, which, in turn, help fight disease. Time will tell if these new drugs fulfill their promise.
Genetic Testing for Disease
In 1986 researchers found a link between genetics and cancer. They isolated (on chromosome 13) and cloned a gene that they believe prevents a hereditary eye cancer called retinoblastoma. Suspect genes are also being investigated for possible links to bone cancer and chronic myeloid leukemia.
Evidence is mounting that genes can promote cancer as well as suppress it. Doctors at UCLA (University of California at Los Angeles) have found that a normal cell may have one or two oncogenes (tumor forming), but a cancer cell may have ten times as many. More oncogenes seem to mean more dangerous tumors, so these researchers are now counting oncogenes in their patients to determine how best to treat them.
All of this is tantalizing, but cancer is not the only disease with a genetic component. A report in Science listed no less than 21 neurological disorders and the genes or chromosomes that appear to be involved in these diseases. The list includes such killers as Alzheimer’s disease, Huntington’s disease, and Duchenne’s muscular dystrophy; nor does the list stop with neurological problems. Genetic markers have also been found for cystic fibrosis, polycystic kidney disease and many other diseases.
All of this raises the intriguing prospect of genetic testing that could tell us if we, or our children, are at high risk of developing one of over 3,000 known hereditary diseases. But it is not quite that simple. Not all such diseases are caused by a single gene. Where multiple genes and other factors are involved, as appears to be the case in Alzheimer’s disease, testing would be difficult. In other cases the actual genes causing the disease have been found and even cloned, but much more often only their general location is known. What has been pinpointed is not the gene itself but a nearby segment of DNA called a genetic marker.
“The map of the human genome as it exists today is very sketchy,” reports Jan Hudis, Science Information Editor for the March of Dimes Birth Defects Foundation. He adds that it “could be compared to a satellite photograph taken when a low cloud cover has obscured all but the highest mountain ranges.”
The Dilemma of Genetic Testing
The promise of widespread genetic testing is great. “In some cases,” notes The New York Times, “the discoveries have made it possible to identify healthy carriers of the disease trait who could pass it on to their children or to make prenatal diagnoses of the condition.” This is certainly valuable information, but, as the Times goes on to point out: “These are triumphs of science, but they do not imply quick conquests of the diseases.” It is one thing to identify a genetically caused disease. Curing it is quite another matter.
There remains the hope that, in time, the actual genes causing more hereditary diseases will be found. Understanding what the genes are supposed to do and what has gone wrong may well lead to therapies as yet unimagined.
In the meantime, parents who undergo genetic testing face hard decisions, perhaps including pressure to abort their unborn offspring. For some of them, abortion will be out of the question, but for others the choice is complicated when markers are tested for and not actual genes. The presence of the marker does not always mean that the gene is present.
“Every year we locate more and more genetic markers for single-gene diseases,” notes Jeremy Rifkin, a vocal critic of biotechnology. “Where do you draw the line? There are several thousand recessive traits. Leukemia can kill your child at three, heart disease at thirty, and Alzheimer’s at fifty. At what point do you say no? Society might even legislate or compel parents not to pass on certain traits because of the health costs likely to be incurred.” It would truly be a sad paradox if a technology meant to save lives and alleviate suffering caused needless deaths of unborn children because someone felt that their genetic traits were “undesirable.”
Leave It to the Lawyers
Interestingly, the very success of the new biotechnology has created a whole new set of problems—fights over the money to be made. “Is litigation becoming the premier product of the biotechnology revolution?” asked Science News, noting that major drug companies are already suing one another and the smaller gene-splicing companies over rights to IL-2, a genetically engineered human growth hormone, and to other marketable drugs.
Patent disputes over drugs are complex enough, but what happens when people start trying to patent genetically altered animals, as permitted by a U.S. patent office ruling last year? Researchers in San Diego have succeeded in splicing firefly genes into tobacco plants, creating plants that glow in the dark! Other tobacco plants have been given a gene from a bacterium to make a protein toxic to plant-eating caterpillars. Maryland scientists have come up with a transgenic pig—a pig with a growth hormone gene from a cow.
Concern Over Trends
This tendency to mix up genes from unrelated species has a number of people concerned. Some farmers’ groups “see genetic engineering as yet another in [a] long line of technologies that favor large corporate farms over small farms.” Animal-rights groups “see it as the ultimate insult to the integrity of animals,” states The New York Times.
“We do not know what life is,” writes Dr. Erwin Chargaff, professor emeritus of biochemistry at the Columbia University medical school, “and yet we manipulate it as if it were an inorganic salt solution.” Dr. Chargaff continues: “What I see coming is a gigantic slaughterhouse, a molecular Auschwitz, in which valuable enzymes, hormones, and so on will be extracted instead of gold teeth.”
Others are alarmed by what they consider to be unknown dangers involved when genetically altered organisms are turned loose in the environment. In 1985 a California company was fined $13,000 when it released altered bacteria without permission. When California courts finally approved similar releases on two test fields in 1987, vandals promptly uprooted the plants. Public concern was again highlighted in 1987 when a Montana plant pathologist inoculated some elm trees with genetically altered bacteria. The scientist in this case was reprimanded because he chose not to delay his experiment for an Environmental Protection Agency review.
The “Holy Grail”?
Meanwhile, genetic research is accelerating. The U.S. Department of Energy has already begun preliminary investigations aimed at determining the precise sequence of all the three billion chemical bases in human DNA. This is a project of breathtaking scale. A printout of the information in human DNA would fill 200 large telephone books. At the current pace, the project could cost untold billions of dollars and require centuries to complete, but rapid advances in sequencing technology are expected to speed things up, cutting time to 15 years, according to the latest estimate. The Department of Energy requested $40 million for the project, and it hopes to increase funding to $200 million per year. Congressional approval must be given.
What is all this money going to buy? Some scientists have compared detailed knowledge of human DNA to the “Holy Grail” of human genetics. They are convinced that it will be a priceless tool for understanding every human function. But others are not so sure.
“While few investigators question the advantage of sequencing a gene of known interest, there is serious question about the immediate value of knowing the precise nucleotide sequence of the entire genome,” observes Jan Hudis, who adds that at this time “only a very small fraction of the total genome is expected to yield information that will have immediate medical value.”
It would indeed be a sad irony if funds urgently needed for medical research were drained away for a scientific megaproject of dubious value.
“We Want Perfect Babies”
Where is the genetic revolution headed? Without question, it contains great potential for good in the form of better drugs, better medical care, and improved understanding of how living things work. But there is another side to the revolution.
“We want perfect babies,” says Jeremy Rifkin. “We want perfect plants and animals. We want a better economy. There’s no evil intent here. The road to the Brave New World is paved with good intentions.
“Step-by-step, we are deciding to engineer parts of the genetic code of living things. Two important questions emerge: If we’re going to engineer the genetic code, what criteria does this society establish for determining good and bad, useful and dysfunctional genes? And I would like to know whether there is an institution anyone here would trust with the ultimate authority to decide the genetic blueprints for a living thing?”
These are questions that deserve answers. Who is better equipped than the Creator of DNA to determine what is a good or a bad gene? He is the one who knows the innermost workings of the genetic code, as is shown by David at Psalm 139:13-16: “You kept me screened off in the belly of my mother. I shall laud you because in a fear-inspiring way I am wonderfully made. Your works are wonderful, as my soul is very well aware. My bones were not hidden from you when I was made in secret, when I was woven in the lowest parts of the earth. Your eyes saw even the embryo of me, and in your book all its parts were down in writing, as regards the days when they were formed and there was not yet one among them.” Would you not prefer to trust Him with the ultimate authority to decide the genetic blueprints for all living things?
[Blurb on page 13]
Who is to decide which genes are good and which are bad?