Genetic Engineering Today: The Promise and the Ethics
Genetic engineering holds the promise of eradicating gruesome genetic disorders that terrorize their victims and plague the families emotionally and financially. Genetic engineering changes a person's genome by introducing new DNA or changing the underlying DNA of the host, providing normal functioning and eradicating disease. Gene therapy is often used to treat genetic disorders that occur when genes are expressed improperly or have a nucleotide insertion or deletion, causing genetic abnormalities. The idea of gene therapy is that a benign virus is used to insert a good copy of the gene into an individual. The newly altered cells are expected to divide as normal. Theoretically, genetic engineering could be used to drastically change individuals' genomes, which could enable people to re-grow limbs and other organs, perhaps even extremely complex ones such as the spine. The promise is that genetic therapy could be used to treat diabetes, cystic fibrosis, or other genetic diseases with replacing the targeted gene. Carriers may make informed choices about their options of having a baby or caring for the baby with a disease. If genetic engineering could be used to replace mutated genes with the healthy ones, then that too is beneficial and can help millions of patients.
Today, human cloning is a common theme in science fiction. It refers to deliberate and creation of a genetically identical copy of a person. There are two types of human cloning: therapeutic and reproductive. Therapeutic cloning involves cloning cells from an adult for use in medicine and medical research. It is critical to note that therapeutic cloning refers to cloning specific cells for specific organs and NOT an entire human being. Therapeutic cloning could have incredible benefits in treatment of diseases: it can deliver genetically identical cells for regenerative medicine and tissues and organs for transplantation. Reproductive cloning is a highly controversial topic and a different matter altogether. It refers to creating an identical copy of a human being. Reproductive cloning could produce benefits for infertile couples so that their baby would have at least some of their genetic characteristics. However, such cloning has not been performed on humans and is illegal in many countries.
Genetic selection procedures can be applied after a foetus or an embryo is tested for a genetic abnormality through prenatal screening or through Preimplantation Genetic Diagnosis (PGD). PGD tests embryos for genetic sequences associated with specific conditions. A cell is extracted from an embryo at its eight-cell stage and analyzed. Embryos with the selected characteristics can be implanted in a woman's uterus to develop into a child. It is believed that the procedure does not affect further development and viability of the foetus, although more testing is required to be certain. This process of implanting the embryos with the specific characteristics is in fact genetic selection because it allows parents who have a known risk to pass a genetic disease to their child to select those embryos unaffected by the mutated gene. It was introduced in 1990 and is used to prevent Down's syndrome, Tay-Sachs disease, cystic fibrosis, sickle cell, Huntington's chorea, and Cooley's anemia. However, PGD has become controversial because some parents want to use it to select the baby's gender or to ensure that siblings of their sick children can provide bone marrow or tissues for transplantation. This technique can even be used to select cosmetic traits, such as eye colour, i.e., design a child. A newer variation of PGD, called Preimplantation Genetic Haplotyping, allows for many more genes to be tested, and for greater accuracy.
One of the biggest considerations surrounding genetic therapy is safety. Although the safety of genetic therapy is of utmost importance to doctors and scientists, risks still exist. Genes are delivered to cells using a delivery vector which are benign viruses. To make the virus usable to deliver gene therapy, disease causing genes of the virus are removed and are replaced with the genes needed by the patient to treat the disease. Then the new virus, carrying the needed genes, is inserted in the patient's cells where they can deliver the needed genetic material. The risks of this procedure include an immune response, where the body rejects and attacks these viruses which in severe cases can cause organ failure. The inserted viruses can attack cells other than the mutated ones for which they were intended. If this happens, the healthy cells can be damaged and cancerous changes can occur. The virus carrying the necessary genes can reverse to its original form and cause disease. The new DNA may affect the reproductive cells, resulting in genetic changes that could be passed to future children. The gene therapy clinical trials under way in the US are closely monitored by the Food and Drug Administration and the National Institutes of Health to ensure the safety of those who participate in the studies.
Ethical considerations of genetic testing are some of the foremost issues facing society today. Some of the burning questions about the ethical considerations of genetic therapy and testing deal with choices surrounding potential termination of pregnancy when a foetus is diagnosed with a genetic disease. Is it ethical to terminate such pregnancy or is it ethical for that child to be born and potentially suffer his or her entire life? Or, if a couple is predisposed to produce a child with a genetic disease, should they be advised not to have children?
Stem cell research promises to deliver many life saving discoveries. Some argue that doing stem cell research on embryos is not ethical because an embryo could have been a beginning of a human life. But if this research is not really hurting any unborn babies, yet it can save the lives of many in the future, why is it a problem? On the other hand, now that the science had advanced and scientists can use adult cell stems, why should the use of embryonic tissue be considered?
In recent years, in-vitro fertilization has become possible and has created another series of questions. For example, since embryos are harvested for fertilization, there may be more viable embryos than are fertilized at any given time. Those embryos are frozen and the question arises as to what to do with them in the future. The woman who owns these embryos has a difficult decision to make: she could have them fertilized and have those babies, or she could give them up for adoption, or she could donate them to science ensuring that they will never become a human life.
In a recent survey of over 2,000 people on their opinions of whether genetic testing is morally justified most people thought that testing for debilitating and terminal diseases including mental retardation was justified, while testing to select certain attributes was not. Some of the concerns with selecting attributes are that parents would select stature and eye and hair colour. This would make our society lose its heterogeneity, changing the make-up of social dynamics. Current reproductive techniques involving in-vitro fertilization allow doctors and parents to do screening and selection to reduce the chance of a child born with a genetic disorder. Currently two types of testing are available. The first allows selection of sperm used to determine the gender of the baby and the genes it will carry. The second, Pre-implantation Genetic Diagnosis (PGD), selects the embryos screened to be free of genetic disease. Another technique, not yet used on humans, has to do with replacing faulty DNA with healthy DNA. Although the PGD procedure is legally allowed, there is little oversight over its safety, especially long-term, since the technology is so new. The new procedure of preconception testing allows the parents to be aware that they are carriers of mutated genes and the likelihood of passing the mutation to their babies. This approach has already helped thousands of families to have healthy babies and to prevent debilitating diseases. The controversies abound with these procedures, despite these benefits. Some people are concerned that carrier and foetus testing will lead to more abortions. Others are concerned that these procedures are used for selection purposes instead of treatment and prevention of serious diseases.
Most of the concerns surrounding genetic engineering are a result of extremes in genetic engineering, the most common one being 'designer babies'. The term designer babies' refers to the parents' ability to select genetic traits for their baby by using genetic testing and genetic selection as part of the IVF process. Although current technology already offers a promise of enabling us to select specific genes to determine specific traits, such technology is in its infancy and risks are high. Today, if we select the 'blue eyes' gene, for example, we do not know what genetic disturbances we introduce in the process and what disorders and deformities this baby might have. Having acknowledged the current limitations, however, in the future we will most likely enhance the selection technology to control that no mutations are introduced when certain genes are selected. Once that happens, medical ethics will determine how widespread this practice will be. Today, we know that genetic testing and therapy to eradicate genetic diseases is widely supported; however, selecting the traits of the unborn child for non-health reasons is not supported by the broader community.
I set up a survey to find out people's opinions on ethics of genetic testing, genetic therapy, and selection for disease related issues and non-disease related reasons using 200 subjects. The subjects were broken down into 3 age categories: under 20, 21-35, and 36 and older because age does influence political and ethical concerns.
The results showed that most people believe that it is ethical to test the foetus for genetic diseases and apply gene therapy to eradicate a disease. 84% of those surveyed believe that genetic testing of a foetus is ethical when testing for a disease, especially if there is a risk factor such as family history or the age of the mother. 89% of those surveyed also said that genetic engineering in the form of inserting or removing genes through gene therapy is, in fact, ethical if disease is involved. However, it was almost unanimous (92% agreement) that selecting traits or designing a baby is unethical. In addition, people are split on whether this practice should be regulated by the government or be a matter of parents' choice. Furthermore, most people believe that it is unethical to do genetic testing and selection for non-disease related characteristics. There was no observed difference in opinions among the three age groups. I was pleased to see that 89% of people believe genetic testing for a disease is ethical. This means that people support scientific progress and allow the removal of disease traits from the foetus. Removal of recessive traits that cause diseases could severely reduce the number of people in the world suffering from genetic diseases. These first steps would allow scientists to continue creating methods that could potentially eliminate disease prone genes from the gene pool and thus eliminate genetic diseases.
The promise of genetic engineering is that it offers technology and knowledge to eradicate life-threatening genetic and acquired devastating diseases, such as cancer; the majority of people endorse such progress. The ethical and safety concerns surrounding genetic testing are valid, but these should not prevent our study and progress in this promising field of science. Stem cell research promises to deliver many life saving discoveries. Some argue that doing stem cell research on embryos is not ethical because an embryo could have been a beginning of a human life. Though there is no consensus on the ethics of using embryonic cells, we hope that in the future we will be able to eradicate diseases even without stem cells. Our capabilities for genetic selection are powerful today and will become even more powerful in the future.
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