This blog post explores the potential for maximizing human capabilities through genetic modification technology and the resulting scientific and ethical issues.
Introduction
Spider-Man, who shoots webs and swings freely through New York’s skyscrapers like Tarzan, remains a movie superhero who still makes my heart race. In The Amazing Spider-Man, protagonist Peter gains spider-like abilities—wall-climbing, enhanced reflexes, and superhuman strength—after being bitten by a genetically modified spider. He harnesses these powers to develop “web-shooters,” devices that shoot out webs, allowing him to move freely through the cityscape. The film also features another genetically altered character, Dr. Curtis Connors. Dr. Connors injects himself with a lizard-derived serum to regenerate his severed arm, but ultimately suffers a catastrophe where his entire body mutates like a lizard. This film is based on the possibility that genetic engineering technology can transfer the characteristics of one organism to another.
While genetic engineering and biotechnology may remain confined to movies and novels, their technological potential is immense, making them the second-most invested-in field among the six major new technologies, following IT. If the movie’s imaginings become reality, we could insert zebrafish genes—known for their exceptional regenerative capacity—into brain cells to treat Alzheimer’s dementia, or even induce physical transformations like those seen in the whale-human hybrid. As we enter the era of 100-year lifespans, humanity is now focusing beyond simply saving lives to preventing disease and enhancing quality of life. Significant efforts are being invested in treating previously incurable genetic disorders. Therefore, this article examines the realistic potential of genetic manipulation technologies seen in movies and presents both positive and negative perspectives on them.
Genetic Manipulation is Possible
Genetic manipulation is entirely feasible and is already being utilized in various fields. However, in organisms with large and complex physical structures like humans, there are limitations to expressing specific traits, and a complete understanding of human metabolism has not yet been achieved. Nevertheless, there are three representative examples where genetic manipulation is being applied in reality.
The first is insulin supplements provided to diabetic patients. Insulin is a protein, which has characteristics that make it difficult to produce chemically on a large scale. Therefore, scientists insert the insulin-producing gene into bacteria or mini-pigs to enable them to produce human insulin, thereby mass-producing insulin. Bacteria are frequently used for genetic manipulation due to their relatively simple structure. Inserting the gene for producing human insulin via a plasmid (a circular DNA molecule existing independently of the cell’s chromosomes) results in bacteria accepting this gene with a certain probability, enabling insulin production. This can be seen as an example of modifying a living organism’s metabolism.
The second example is GMO foods. These are typically developed to combine the advantages of multiple plants, creating superior plants compared to existing ones. A prime example is the ‘fish tomato’. This tomato incorporates genes from deep-sea fish, specifically the ‘cold tolerance gene’ from flounder, enabling it to thrive even in low temperatures. Introducing characteristics from other organisms to alter the traits of a specific life form is an example of genetic manipulation.
The third example is GloFish, created by injecting GFP (Green Fluorescent Protein) derived from jellyfish into fish embryos, resulting in fluorescent fish that glow brightly under ultraviolet or white light. Initially, only green-glowing fish existed, but today, using jellyfish and coral genes, fluorescent fish of various colors are being created. These genetic engineering examples suggest that trait transformation, such as fluorescent humans or humans with cold resistance, is theoretically possible. As seen in these three examples, trait transformation through genetic engineering is not impossible.
Genetic manipulation is impossible
However, it is argued that freely manipulating human genes remains impossible. This is due to ethical concerns, as it is akin to challenging the realm of God, and also because our understanding of genes themselves is still insufficient. Although the ‘Human Genome Project’, which mapped the entire human genetic sequence, was completed in 2003, this is merely the chemical sequence. Research is still ongoing into what specific proteins particular genes encode and how they interact. For instance, to create a fluorescent human where the fluorescent protein is produced only in the skin, one must be able to strictly control the processes of cell differentiation and development. Both Differentiation and Pattern Formation are involved in gene expression. For fluorescent DNA to be expressed only in skin cells and suppressed in others, specific proteins are required, and another gene must exist to produce those proteins. Thus, genetic manipulation is not merely a matter of inserting DNA; it involves highly complex theoretical work.
Even if all relevant genes are identified and manipulated at the embryonic stage, problems can still arise. With current technology, injecting genes into an embryo can cause the cells to reject the foreign material or die. Even if the gene is inserted into the cell, it remains uncertain whether this DNA will stably integrate within the cell and successfully express the protein.
Furthermore, acquiring multiple species’ traits simultaneously, like in the movie Spider-Man, is even more nearly impossible. For instance, to manifest all the necessary traits—like the fine hairs for climbing walls, rapid reflexes, and powerful muscles—multiple genes would need simultaneous manipulation. This would likely drastically alter the original human body structure. Enhancing reflexes would require changes to neural structures, which may be unrelated to spider genes. Ultimately, human genes have evolved over vast periods to reach an optimal state, making such large-scale alterations extremely difficult.
Conclusion
The emergence of beings like Spider-Man or lizard-humans from movies is highly improbable in reality. The traits genetically shareable between humans and spiders are extremely limited, and genetic changes substantial enough to alter a creature’s fundamental nature require adaptation and evolution. Gene expression isn’t merely about protein production; it occurs only when various factors interact. Therefore, the creation of a ‘Genetically Modified Human’ would require solving numerous scientific challenges.
Even if technology advances to the point of creating beings like superheroes, this would face ethical issues. If such abilities were used to oppress the weak, perhaps all of humanity would need to undergo genetic modification to ensure fairness. However, not everyone would want such modification.
Genetic manipulation within a person’s basic genetic makeup would likely spark less ethical controversy and would not be considered dangerous experimentation. Manipulation within the basic genetic makeup refers to interventions aimed at restoring functions lost due to genetic mutation. For example, enabling the body to produce insulin internally, rather than relying on externally produced and ingested insulin, is beneficial to health. Furthermore, treating conditions like cystic fibrosis caused by genetic mutation falls under medical genetic manipulation. Since films prioritize entertainment over scientific accuracy, we must identify real-world problems and fulfill our responsibilities as biomedical scientists to advance genetic manipulation that benefits society.
