As most people who read textbooks and things know, recombinant DNA technology started with pretty simple things--cloning very small pieces of DNA and growing them in bacteria--and has evolved to an enormous field where whole genomes can be cloned and moved from cell to cell, to cell using variations of techniques that all would come under genetic engineering as a very broad definition. To me, genetic engineering, broadly defined, means that you are taking pieces of DNA and combining them with other pieces of DNA.
And then taking what you have engineered and propagating that in any number of different organisms that range from bacterial cells to yeast cells, to plants and animals. So while there isn't a precise definition of genetic engineering, I think it more defines an entire field of recombinant DNA technology, genomics, and genetics in the s. Moreover, such insights can assist in the development of guidelines and policies.
Much of what we currently know about the ramifications of genetic self-knowledge comes from testing for diseases. Once disease genes were identified, it became much easier to make a molecular or cytogenetic diagnosis for many genetic conditions.
This sort of testing is a particularly attractive choice for individuals who are at risk for diseases that have available preventative measures or treatments, as well as people who might carry genes that have significant reproductive recurrence risks. Indeed, thanks to advances in single-cell diagnostics and fertilization technology, embryos can now be created in vitro ; then, only those embryos that are not affected by a specific genetic illness can be selected and implanted in a woman's uterus.
This process is referred to as preimplantation genetic diagnosis. For adult-onset conditions , ethical concerns have been raised regarding whether genetic testing should be performed if there is no cure for the disease in question. Many people wonder whether positive diagnosis of an impending untreatable disease will harm the at-risk individual by creating undue stress and anxiety.
Interestingly, social science research has demonstrated that the answer to this question is both yes and no. It seems that if genetic testing shows that an individual is a carrier for a recessive disease, such as Tay-Sachs disease or sickle-cell anemia , this knowledge may have a negative impact on the individual's well-being, at least in the short term Marteau et al.
For many people who choose to have predictive testing, gaining a locus of control by having a definitive answer is helpful. Some people are grateful for the opportunity to make life changes—for instance, traveling more, changing jobs, or retiring early—in anticipation of developing a debilitating condition later in their lives. Of course, as genetic research advances, tests are continually being developed for traits and behaviors that are not related to disease.
Most of these traits and behaviors are inherited as complex conditions, meaning that multiple genes and environmental, behavioral, or nutritional factors may contribute to the phenotype. Currently, available tests include those for eye color, handedness, addictive behavior, "nutritional" background, and athleticism.
But does knowing whether one has the genetic background for these nondisease traits negatively affect one's self-concept or health perception?
Studies are now beginning to address this question. For example, one group of scientists performed genetic testing for muscle traits on a group of volunteers enrolled in a resistance-training program Gordon et al. These tests looked for single-nucleotide polymorphisms that would tell whether an individual had a genetic predisposition for muscle strength, size, and performance.
The investigators found that if the individuals did not receive affirmative genetic information regarding muscle traits, they credited the positive effects of the exercise program to their own abilities. However, those study participants who did receive positive test results were more likely to view the beneficial changes as out of their control, attributing any such changes to their genetic makeup.
Thus, a lack of genetic predisposition for muscle traits actually gave subjects a sense of empowerment. Another matter bioethicists often consider is that people may discover that they carry some genes associated with physiological or behavioral traits that are frequently perceived as negative. Moreover, many critics fear that the prevalence of these traits in certain ethnic populations could lead to prejudice and other societal problems.
Thus, rigorous social science research by individuals from diverse cultural backgrounds is crucial to understanding people's perceptions and establishing appropriate boundaries. Over the years, the desire for better sports performance has driven many trainers and athletes to abuse scientific research in an attempt to gain an unjust advantage over their competitors.
Historically, such efforts have involved the use of performance-enhancing drugs that were originally meant to treat people with disease. This practice is called doping, and it frequently involved such substances as erythropoietin, steroids, and growth hormones Filipp, To control this drive for an unfair competitive edge, in , the International Olympic Committee created the World Anti-Doping Agency WADA , which prohibits the use of performance-enhancing drugs by athletes.
WADA also conducts various testing programs in an attempt to catch those athletes who violate the anti-doping rules. Today, WADA has a new hurdle to overcome—that of gene doping. This practice is defined as the nontherapeutic use of cells, genes, or genetic elements to enhance athletic performance. Gene doping takes advantage of cutting-edge research in gene therapy that involves the transfer of genetic material to human cells to treat or prevent disease Well, Because gene doping increases the amount of proteins and hormones that cells normally make, testing for genetic performance enhancers will be very difficult, and a new race is on to develop ways to detect this form of doping Baoutina et al.
The potential to alter genes to build better athletes was immediately realized with the invention of so-called "Schwarzenegger mice" in the late s. These mice were given this nickname because they were genetically engineered to have increased muscle growth and strength McPherron et al. The goal in developing these mice was to study muscle disease and reverse the decreased muscle mass that occurs with aging.
Interestingly, the Schwarzenegger mice were not the first animals of their kind; that title belongs to Belgian Blue cattle Figure 1 , an exceptional breed known for its enormous muscle mass. These animals, which arose via selective breeding , have a mutated and nonfunctional copy of the myostatin gene , which normally controls muscular development.
Without this control, the cows' muscles never stop growing Grobet et al. In fact, Belgian Blue cattle get so large that most females of the breed cannot give natural birth, so their offspring have to be delivered by cesarean section.
Schwarzenegger mice differ from these cattle in that they highlight scientists' newfound ability to induce muscle development through genetic engineering, which brings up the evident advantages for athletes.
But does conferring one desirable trait create other, more harmful consequences? Are gene doping and other forms of genetic engineering something worth exploring, or should we, as a society, decide that manipulation of genes for nondisease purposes is unethical? Genetic testing also harbors the potential for yet another scientific strategy to be applied in the area of eugenics , or the social philosophy of promoting the improvement of inherited human traits through intervention.
In the past, eugenics was used to justify practices including involuntary sterilization and euthanasia. Today, many people fear that preimplantation genetic diagnosis may be perfected and could technically be applied to select specific nondisease traits rather than eliminate severe disease, as it is currently used in implanted embryos, thus amounting to a form of eugenics.
In the media, this possibility has been sensationalized and is frequently referred to as creation of so-called "designer babies," an expression that has even been included in the Oxford English Dictionary.
Although possible, this genetic technology has not yet been implemented; nonetheless, it continues to bring up many heated ethical issues. Trait selection and enhancement in embryos raises moral issues involving both individuals and society. First, does selecting for particular traits pose health risks that would not have existed otherwise? The safety of the procedures used for preimplantation genetic diagnosis is currently under investigation, and because this is a relatively new form of reproductive technology, there is by nature a lack of long-term data and adequate numbers of research subjects.
Still, one safety concern often raised involves the fact that most genes have more than one effect. For example, in the late s, scientists discovered a gene that is linked to memory Tang et al. Modifying this gene in mice greatly improved learning and memory, but it also caused increased sensitivity to pain Wei et al.
Beyond questions of safety, issues of individual liberties also arise. For instance, should parents be allowed to manipulate the genes of their children to select for certain traits when the children themselves cannot give consent? Suppose a mother and father select an embryo based on its supposed genetic predisposition to musicality, but the child grows up to dislike music.
Will this alter the way the child feels about its parents, and vice versa? Finally, in terms of society, it is not feasible for everyone to have access to this type of expensive technology. Such impairment can result in disablement in our society. People with disabilities are often discriminated against by having fewer opportunities than other people. Be removing genetic disorders, and resulting impairment, it is true that gene therapy could contribute to removing one of the sources of discrimination and inequality in society.
But the implicit assumption being made, the objection claims, is that people impaired through genetic factors need to be treated and made normal. The objection sees gene therapy as a form of discrimination against impaired people and persons with disabilities. The irrelevance objection is that gene therapy on reproductive cells may in some cases already be superseded by in-vitro fertilization and selection of embryos.
If a genetic disorder is such that can be detected in an early embryo, and not all embryos from the parent couple would have it, then have parents produce multiple embryos through in-vitro fertilization and implant only those free from the disorder. In such a case gene therapy would be unnecessary and irrelevant. Ethicists have generally been even more concerned about possible problems with and implications of enhancement genetic engineering than they have been about gene therapy. First, there are worries similar to those about gene therapy that not enough is known and there may be unforeseen dangerous consequences.
These worries may be even more serious given that the attempts are made not just toward normalcy but into strange new territory where humans have never gone before.
We just do not know what freakish creatures might result from experiments gone awry. Gene therapy is becoming a reality as you read this. Genetic engineering for enhancement is still a ways off. Plenty of debate is sure to occur over both issues. Columbia, MO Contact. All rights reserved. DMCA and other copyright information.
For website information, contact the Office of Communications. Contact the MU School of Medicine. Informational Alert Close. Learn how to schedule an appointment for vaccination or testing. Read More. Education Research Patient Care. Student Resources Faculty Resources. More Search. Can't find what you're looking for? Pages No Results. Center for Health Ethics. Section Menu. Confusing Terminology If genetic engineering is meant in a very broad sense to include any intentional genetic alteration, then it includes gene therapy.
Somatic Cells and Reproductive Cells Two fundamental kinds of cell are somatic cells and reproductive cells. Techniques of Genetic Alteration Two problems must be confronted when changing genes. Arguments in Favor of Gene Therapy and Genetic Engineering Gene therapy is often viewed as morally unobjectionable, though caution is urged.
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