Gene therapy is a controversial issue in today’s science society. Debates in the United States are covering a wide range of topics. I will discuss just a few viewpoints from both sides.
First of all, a little background on DNA and genetics. DNA, or deoxyribonucleic acid, is a complex structure consisting of a double stranded helix made up of complementary base pairs. Adenine (A) pairs up with thymine (T) and guanine (G) matches with cytosine (C). They are held together with the help of hydrogen bonds. The helix is spiral shaped, and the outside of DNA is alternating sugar and phosphate groups. Watson and Crick presented this structure in 1953.
"The genetic code is imprinted in the precise sequence of the nitrogenous bases running down the length of DNA molecule." Lee, 1993. A base triplet code is made up of three nucleotides. Each DNA triplet code is translated via a messenger RNA into a protein. DNA has a semiconservative replication process where the double strands unwind and serve as templates.
A genome is a collection of DNA molecules that make up am organism. There is great diversity between different species and even between the same species. "The human genome contains up to three billion base pairs, the genetic difference among individual humans is as much as three million base pairs of DNA" (Davis, 1990).
A mutation is where a gene is changed to another form. A mutation does not imply a bad thing happened. They can be deleterious, cause disease, reduce fitness or even be lethal. A mutation can also be beneficial if it increases adaptability or advantages in a species. Or a mutation can be silent and cause no apparent change in the organism. This can happen when a nucleation codes for the wrong base, but the same amino acid is formed.
What would happen if the mutation could be covered up, taken out or replaced? This is exactly what gene therapy is all about. It is putting a healthy gene into cells that have a faulty copy of that gene. According to the Oxford dictionary, gene therapy is defined as a "curative medical treatment." The mutagens, or mutant-causing genes, are being replaced by "normal" ones. According to Thomas F. Lee, 1993, there are four kinds of therapy:
A conference at Asilomar, CA, in February 1975, was scheduled for scientists, lawyers, press and government officials. A new era of technology was developing and they wanted to make sure experiments were safe for lab workers and the general public. As a consequence, the NIH (National Institute of Health) created strict guidelines classifying experiments in 1976. The press amplified the level of fear in the public. They concentrated on the potentially dangerous strains. People were scared a normal gene could be transformed into a resistant pathogen to humans.
The NIH created the Recombinant DNA Advisory Committee (RAC) to review proposals. All funding research grants given by the NIH are interviewed by the RAC. The original had committee had 12 members, but later expanded to 20 because of an increasing diversity from experts in other fields. After legislation of congress, the RAC was given a bigger responsibility. Now, more than 20 years later after the conference, most of those guidelines are relaxed and most experiments continue with no restrictions.
The key to knowing more about genes was to try and make a map of the genome. A genetic map shows a location of a gene or a group of related genes. A physical map shows the location of landmarks on a DNA strand. The idea of mapping out the human genome to try and locate disease sparked scientists into forming the Human Genome Project. "The Human Genome Project will revolutionize the practice of medicine. It will utterly change the field of genetics." Davis, 1990. It began in 1991 and the original goal was a 15 year, $3 billion budget program. "The Human Genome Program in the U.S. will provide about $200 million each year to scientists in multidisciplinary research centers who are attempting to determine the makeup of all human genes." BIO, 1990.
Most people who are against gene therapy are using an ethical background. They argue that a person should live with the genes they were born with and let fate determine life. It is even considered sinful in some religions to manipulate your DNA. Some people claim it would harm the next generation because of possible side effects to infants by introducing new genes.
Eugenics is also a debatable topic. As previously defined, eugenics caused a great deal of discrimination and death in Germany because of the Nazi regime. They had an idea of what they thought was the superior race and what was the ideal human. But the whole idea of gene therapy is to make sick people normal and not normal people superior.
Even if eugenics isn’t the goal, other properties of enhancement are involved. Random mating occurs in the world, for most species. A person doesn’t look for a certain genome, but perhaps a few traits: intelligence, athletic ability and appearance for example. It isn’t just in the human species that enhancement is desired. Those animals that are faster, smarter and better hunters will survive and produce more offspring. But to alter a genome to become taller or for blue eyes is not gene therapy. This kind of therapy isn’t considered necessary and short and long term effects are quite possible. It is ironic that some people who have the money to research diseases are looking for enhancement techniques.
Some pessimists also claim our gene pool would change, maybe even developing into a new species. I believe our gene frequency is changing anyway. The change may be a slow process, but eventually a species has to evolve to adapt to the continually changing environment. The species Homo sapiens evolved from many different gene pool changes. Stephen Jay Gould, a paleontologist, said about Homo sapiens, " a tiny twig on an improbable branch of a contingent limb on a fortunate tree." It all depends on what you call a normal trait or a disease.
Another group of concerned people argues that it is an invasion of privacy. If an insurance company has a mandatory genome test for disease, and a family proves positive—will they be discriminated, be rejected for high risk, or have to pay more then a nonaffected family? Or if their results are given out to employers—will it prevent them from getting a job, promotion, or a raise? All of these questions haven’t been answered, but discrimination isn’t allowed in any other form in the United States and I would hate to see health care affected. These problems are exactly the reason why curing a disease with gene therapy would be so helpful. The other side of the coin is if they do develop a cure for a certain disease and the family chooses not to go through therapy, would the insurance rates be effected?
Lastly, one of the most important questions some people may ask is, " Do I really want to know?" It is a serious internal question probing idea. Does a person want to know they have Alzheimer’s or Hungtington’s disease? It may effect their whole life knowing that they will someday not be able to function normally and could pass that defective gene to the next generation.
Some opinions supporting the gene therapy concept is the obvious idea of curing disease. "According to a survey reported by the Office of Technology Assessment, 83 percent of the public say they approve of the human cell manipulation to cure usually fatal genetic diseases." U.S. Congress, 1990. I would think that most people would take advantage of the therapy, if they could afford it.
Gene therapy could become a very efficient way of curing disease. Instead of receiving chemotherapy for several months to years for cancer, you could get gene therapy sessions that are relatively painless and will permanently cure cancer.
It also a good technique for diseases that aren’t well researched. All of us carry some defective genes, but don’t realize it until we are affected by it. "About one in ten people has, or will develop at some later stage, an inherited genetic disorder, and approximately 2,800 specific conditions are known to be caused by defects (mutations) in just one of the patient’s genes" BIO, 1990
. As explained earlier, DNA matches up to complementary base pairs. This is a very important concept to remember when using gene therapy. Because of these matching pairs, DNA probes are used to attach to the defective DNA and hopefully repair it. It is usually most successful when the disease is targeted in one area, or organ. DNA probes are specially designed to bond to certain sequences and that is why is pertinent that we map out the Human Genome.
After all the discussion that is currently available about gene therapy, I think my opinion is clear. Gene therapy is a next step in modern medicine and many improvements are being made every month. It is becoming a safer, more efficient process that may some day cure the world of all genetic disease. Some day, being sick may just mean getting gene therapy.
Joel Davis, Mapping the Code: The Human Genome Project and the Choices of Modern Science, John Wiley & Sons, Inc., 1990.
Thomas F. Lee, GENE FUTURE: The Promise and Perils of the New Biology, Plenum Press, New York, 1993.
U.S. Congress, Office of Technology Assessment, New Developments in Biotechnology—Background Paper, Pubic Receptions of Biotechnology, OTA—BBP—BA—45, U.S. Government Printing Office, Washington, D.C., May 1987 quoted by George J. Annas and Sherman Elias, GENE MAPPING: Using law and Ethics as Guides, Oxford University Press, New York, 1992, page 144.
Unknown author, Gene Therapy - An Overview, 1990, http://www.gene.com/AE/AB/IWT/Gene_Therapy_Overview.html