Genetically modified animals have the potential to help cure diseases and solve food shortages, but ethical issues and the need for safety verification remain a major topic of discussion.

Introduction

With the development of genetic engineering and the ability to manipulate the traits of living organisms, research on gene function and the scope of its application has been actively pursued. In particular, the genetic modification of animals and plants and how it can improve human life remains a hot topic of interest.
Genetic engineering of animals refers to the artificial manipulation of an animal’s genes to modify the function of its genes. Traditionally, genetically engineered animals have been used to increase animal productivity through the selection and breeding of superior breeds and improved specification management techniques. However, as technology advances, the scope is expanding.

What is genetic engineering?

Genetic modification is practiced in a variety of ways in animals such as mice, rabbits, and cows. However, for the sake of this topic, we’re going to focus on the case of genetically engineered pigs because of the ethical considerations involved.
Genetically engineered pigs are developed for a variety of reasons in different fields. For example, they are sometimes engineered to explosively increase the amount of muscle they have, like the super pig in the movie Okja by South Korean director Park Chan-wook, or they are genetically engineered to be resistant to porcine epidemic diarrhea (PED). Muscle pigs are efficient because they require less time and money to develop new pig breeds, and PED-resistant pigs are effective at stopping PED infections and developing vaccines, demonstrating the great benefits of animal genetic engineering.
However, these pigs are not the only ones. As mentioned earlier, genetically engineered pigs are developed for a variety of purposes. Among them are pigs developed for human benefit and to improve the quality of life. While the two examples of pigs in the previous paragraph may be ethically problematic because they ultimately seek efficiency as human food, pigs developed to treat human diseases and as alternatives to life are more ethically problematic and require more discussion in society. Therefore, in this article, we will discuss genetically engineered pigs in more depth, with the exception of the cases mentioned in the previous paragraph.

Disease model pigs

First, there are “disease model pigs” that suffer from diseases similar to those in humans. Also called “immunodeficient pigs,” these genetically engineered pigs are either born from surrogate mother pigs through somatic cell nuclear transfer or are developed by transplanting human tissue. The most commonly used method is the transplantation of human tissue, which has the advantage of being relatively easy to develop because the pig does not develop an immune response to the transplanted tissue. For example, transplanting human tissue from a pig with liver cancer into a pig creates a pig with liver cancer, or transplanting skin from an atopic patient into a pig creates a pig with atopic disease.
A specific disease example is dementia. According to 2014 health insurance statistics, about 70,000 people in Korea suffer from dementia. However, treatments are only able to improve cognitive function. Currently, clinical trials, an important step in the drug development process, use mice to test the toxicity of drugs, but due to the genetic distance between mice and humans, what works in mice often fails in clinical trials. An alternative to this is the use of large animals, the most commonly mentioned of which is pigs.
In 2016, a team of professors at Seoul National University’s College of Veterinary Medicine unveiled a “dementia pig” that exhibited behaviors similar to those of dementia patients, such as an inability to find simple paths and forgetting the location of automatic water fountains. These pigs are genetically engineered animals designed to treat dementia in humans.

Chimeric pigs

The second is the “chimeric pig,” which has human organs. According to statistics from the Center for Organ Transplantation Management, as of 2014, only 15% of those waiting for an organ transplant receive one, and 220,000 patients die every day due to organ shortages. To solve this problem, research is being conducted on xenograft transplantation, in which organs from pigs are transplanted, and chimeric pigs, in which human organs are grown in the bodies of pigs.
You may not be familiar with the term chimeric pig, but chimera refers to the coexistence of tissues with different genetic properties in the same individual. Chimeric pigs are genetically engineered animals that were created as an alternative to human organ transplants.
In 2016, a team of researchers in the United States injected human induced pluripotent stem cells (iPS) into pig embryos that had been genetically edited to not grow a pancreas, and then implanted them in the uterus of a surrogate pig. The iPS cells injected in this experiment were developed by a team of professors at Kyoto University in Japan. iPS cells are pluripotent stem cells that can reverse differentiate into different tissues. Therefore, while the pig embryos in the study did not have the genetic information to make a pancreas, they could “theoretically” differentiate into a pancreas with the injection of iPS cells.
However, even if the pancreas differentiates successfully, it cannot be transplanted directly into a human. This is because while the pancreatic cells are human, the blood vessels that connect them are still pig. This is why this research is still ‘theoretical’.
In addition, pigs have a peculiar sugar in their vascular endothelium that humans don’t have. Its exact name is alpha 1,3 galactose transferase. Since primates, including humans, are born with natural antibodies to this sugar, transplanting a pig vascularized organ into a human will result in immune rejection, and the transplanted organ will be destroyed within minutes or hours.
Because of these problems, several professors have suggested that the next experiment should involve injecting human iPS cells into pig embryos with edited blood vessel-making genes, as was done in the case of pancreas editing. If the final experiment is successful, pigs would have human blood vessels, which would solve the immune problem to some extent.
While these chimeric embryo and chimeric pig studies hold great promise for cross-species liver transplants, they are also hotly debated ethically. In September of last year, the U.S. National Institutes of Health announced that it would stop funding research that involves injecting human stem cells into other vertebrate embryos during the blastocyst stage, the stage before the embryo differentiates into tissues and organs. The aforementioned U.S. research team said it was conscious of the ethical issues and only grew the chimeric pig-human embryos for 28 days in the surrogate mother’s womb.

Advantages of genetically engineered animals

Genetically engineered animals are efficient in developing new breeds because their genes are artificially edited and corrected. It takes less time than the traditional method of waiting for mutations to appear naturally, and it’s also less expensive. As a result, genetically engineered animals can produce better, higher-quality animals.
Using pigs as an example, genetically engineered pigs can revolutionize the pig farming and livestock industry, with pigs that are more tender and tender in meat, and pigs that can more than double their muscle mass when fed similar amounts to normal pigs. This is due to their high productivity.
Genetically engineered animals are also an effective catalyst for the development of cures for human diseases. This is because they allow for personalized medicine.
Like genetically modified plants, genetically engineered animals have the potential to gradually solve the human food crisis.

Ethical issues with genetically engineered animals

However, the ethical issues that come with these technologies cannot be easily overlooked. Specifically, in the case of chimeric pigs, there is the possibility that iPS cells could differentiate into tissues other than the targeted organ. This is an extreme example, but if they differentiate into the brain, it could affect the animal’s cognitive abilities, which is ethically problematic from an animal rights and protection perspective.
There is also the question of safety. There are currently no genetically engineered pigs on the market for human consumption, but if they were to be commercialized one day as an alternative to food shortages or other problems, it would be essential to verify their safety. Research is needed to determine the effects of consuming these animals on the human body and how they will affect future generations if they accumulate in the long term.
Along with ethical issues, there are also important legal aspects. As genetic manipulation techniques have evolved, there are many different ways to do it, from inserting genes that didn’t exist before to creating microscopic mutations, and the risks vary. While such research is essential for the advancement of life sciences, there is a need to discuss the scope, standards, and risks of such research along with the ethical issues.

Conclusion

From an ethical point of view, I’m against genetically engineered animals. I don’t think it’s right to violate the rights of animals and create a large number of unwanted, artificially mutated animals.
Also, when it comes to animal organ transplants, it’s not just digestive organs such as stomachs and livers, but as technology becomes more advanced, pig brains, which are responsible for cognitive functions, could be transplanted into humans. If I were in this situation, I would be confused and struggle with my identity.
In addition to the ethical issues, technological advances that go against the grain of nature scare me. I think people should be more alert to how these technological advances will affect us as humans.
If life sciences become more advanced and technology more sophisticated, the benefits of genetically engineered animals could be even greater than they are now. There will be more impacts on humans, and there is no way to stop the advancement of technology. Genetic animal research will continue. But there will always be a need to discuss the ethical issues it brings, and to have social agreements and rules that take into account the risks. I believe that there are benefits to genetic engineering, and we should use them to promote a healthy coexistence between animals and humans.