This blog post explores the possibilities and dangers an era where genetic engineering replaces natural selection might bring, deeply contemplating whether humanity can truly be safe amidst a changing environment.
What would society look like if science and technology advanced to the point of manipulating genes? The 1997 film Gattaca offered an indirect glimpse of this future. In the movie, a couple bypasses natural conception, instead selecting desired genetic traits—height, skin tone, facial features, personality—for their child in a laboratory. Based on this, a geneticist manipulates the embryo’s genes, and the parents conceive through artificial insemination. Since parents naturally wish for their child to inherit only healthy genes and avoid illness, if this technology becomes commercially available, artificial insemination would likely be preferred over natural conception without genetic manipulation. At first glance, this might seem like a desirable technology, as it removes undesirable genes beforehand and passes on only good genes to the child. However, if humans intervene in determining an embryo’s genes, this could pose a significant risk to humanity’s survival.
Humans appeared approximately 3 million years ago and have evolved to adapt to their environment ever since. The most crucial factor in this evolutionary process is natural selection. Natural selection refers to the process where, when environmental changes occur in an ecosystem, individuals within a diverse population that adapt well to the changes survive. The gene pool determines the survival probability of these individuals. The gene pool signifies the total amount of genetic information contained within a biologically viable population over a given time. The larger the gene pool, the greater the variety of genetic information it holds, increasing the likelihood of possessing genes capable of responding to sudden changes. In other words, humans were able to survive and evolve over approximately 3 million years thanks to this natural selection and genetic diversity. It is thought that humanity survived because, through meiosis, individuals possessing diverse genes rather than a single gene were produced.
This issue is not unique to humans. Ecosystems have experienced drastic changes long before humans appeared, and each time, individuals adapted to environmental shifts survived. Conversely, organisms unable to adapt became extinct. Dinosaurs are a prime example. While the exact reason dinosaurs vanished from Earth remains unclear, the crucial point is that mammals survived. This natural selection is not solely a matter of the past. Even today, species unable to adapt to their environment face extinction. A prime example is the banana. Currently, bananas worldwide are suffering from an infectious disease called ‘Panama disease’. This disease infects the soil around banana tree roots, preventing them from bearing fruit. But why could a single infectious disease threaten the extinction of countless banana trees globally?
The answer lies in a lack of genetic diversity. The Cavendish banana, which currently accounts for 45% of global banana production, was cultivated as the primary variety due to its advantages in size and yield, outcompeting other cultivars.
However, the Cavendish lacked the genetic defenses to withstand the sudden outbreak. Consequently, many Cavendish banana trees are dying, and efforts to develop new varieties are underway. Environmental changes can occur at any time, and a large gene pool is essential for adaptation and survival. Yet, if genetic modification is permitted, there is concern that the genetic information of many people could become homogenized, leading to a shrinking gene pool.
Furthermore, permitting genetic modification of embryos would likely eliminate genes currently deemed useless. Yet humans do not fully understand the potential functions of all genes. Even genes considered harmful today could play a vital role in human survival during sudden, drastic changes. To illustrate this, consider sickle cell anemia. Sickle cell anemia is a genetic disorder where red blood cells deform into a sickle shape due to a gene mutation. This disease confers resistance to malaria; individuals with this gene are less susceptible to malaria. However, the red blood cells break down easily, causing severe anemia. The distribution of this disease closely matches the distribution of malaria. This implies that the sickle cell gene underwent natural selection in Africa, where malaria was prevalent. Had the resistance of sickle cells to malaria not been discovered, many would have naturally sought to eliminate this gene. Yet, if a variant malaria were to become an epidemic later, humanity without the sickle cell gene would face a major crisis. As this example shows, we must not recklessly eliminate genes because we are unaware of the latent capabilities of countless others.
Some might counter that if humans could possess only superior genes through genetic manipulation, humanity would evolve to gain survival advantages. However, genetic manipulation would likely favor traits deemed advantageous from a contemporary perspective. While it might protect humans from disease and extend lifespan, it is uncertain whether a gene pool homogenized by social convention could flexibly adapt to future drastic environmental changes. Rather, a tragic outcome like that of the Cavendish banana seems more natural.
The film begins by quoting Ecclesiastes 7:13 from the Bible. “Consider God’s handiwork; who can straighten what He hath made crooked?” Meaning, what is crooked has its own significance. Human genetic information is the result of natural selection through a long evolutionary process. Therefore, it has meaning in itself and should not be altered recklessly. Environmental changes have already driven many species beyond bananas to extinction. We must always remember that we could be next.
