Can genetic engineering allow humans to override natural selection and adapt to environmental changes?

As technology advances and genetic manipulation becomes possible, humans will be able to select children with desired traits. However, if we lose genetic diversity, we risk disrupting the natural selection process and running out of genes to adapt to rapid environmental changes. Human genetic information is a product of natural selection and should not be tampered with.

 

What would a society look like if science and technology could manipulate genes in the future? The 1997 movie Gattaca indirectly answered this question. In the movie, a couple doesn’t conceive naturally, but instead selects the genetic traits they want for their child in a lab: height, skin color, face shape, personality, etc. Geneticists then manipulate the genes in the embryo, and the parents give birth to the child through artificial insemination. Parents want their children to be healthy and to inherit only healthy genes, so if this technology is commercialized, artificial insemination will be preferred to natural conception without genetic manipulation. At first glance, it may seem like a desirable technology because it eliminates the bad genes in advance and gives the child only the good ones. However, if humans are involved in determining the genes of an embryo, this could pose a major risk in terms of human survival.
Humans appeared about 3 million years ago and have been evolving to fit into their environment ever since. Natural selection is the most important part of this evolutionary process. Natural selection is when an environmental change occurs in an ecosystem, and among the various populations, the ones that are better adapted to the change survive. It is the gene pool that determines the probability of an individual’s survival. The gene pool is the total amount of genetic information contained in a population of organisms that can reproduce within a given time. The larger the gene pool, the more diverse the genetic information, and the more likely it is that there will be genes that can respond to rapid changes. In other words, it is thanks to this natural selection and genetic diversity that humans have been able to survive and evolve for about 3 million years. It’s thought that we’ve been able to survive because meiosis creates individuals with a variety of genes rather than a single gene.
This problem is not unique to humans. Ecosystems have been undergoing drastic changes since long before humans arrived on the scene, and in every case, the individuals that adapted to the changes in their environment have survived. Those that didn’t adapt have gone extinct. We still don’t know exactly why dinosaurs disappeared from the face of the earth, but the important thing is that mammals survived. Natural selection isn’t just a thing of the past. Even today, there are creatures that are at risk of extinction due to their inability to adapt to their environment. A prime example of this is the banana. Currently, bananas are suffering from an epidemic called Panama disease, which is spreading around the world. It’s an infectious disease that contaminates the soil at the roots of banana trees, preventing them from producing fruit. But why can one disease threaten so many banana trees around the world with extinction? The answer is a lack of genetic diversity.
The Cavendish banana, which currently accounts for 45% of the world’s banana production, has been cultivated as the dominant variety due to its size and yield advantages. However, Cavendish bananas do not have the genes to respond to sudden outbreaks of infectious diseases, so many Cavendish banana trees are dying, and efforts are underway to develop new varieties. Environmental changes like this can happen at any time, and it takes a large gene pool to adapt and survive. However, if genetic modification is allowed, it could lead to the homogenization of many people’s genetic information and shrink the gene pool.
Also, if genetic modification of embryos is allowed, genes that are currently considered useless will be eliminated. However, humans do not know all the potential functions of genes. Even genes that are currently considered harmful may play an important role in the survival of the human race in times of drastic change. To illustrate this point, consider sickle cell anemia, a genetic disorder in which a gene abnormality causes red blood cells to become sickle-shaped. This makes them resistant to malaria, and people with this gene are less susceptible to malaria. However, the red blood cells are easily destroyed, causing severe anemia. The distribution of this disease closely matches the distribution of malaria. This means that the sickle cell gene has been naturally selected for in Africa, where malaria is common. If it hadn’t been discovered that sickle cells were resistant to malaria, many people would have naturally tried to eliminate the gene. However, if a subsequent strain of malaria were to become an epidemic, the loss of the sickle cell gene would be a major crisis for the human race. As this example illustrates, we don’t know the latent abilities of many genes, and we shouldn’t remove them recklessly.
Some might argue that if genetic manipulation allows humans to have only the better genes, it would be beneficial for humanity to evolve and survive. However, genetic manipulation will be directed toward adopting traits that are considered advantageous from a contemporary perspective. While it may protect humans from disease and extend their lifespan, it is unclear whether a gene pool that is homogenized by social convention will be flexible enough to cope with rapid environmental changes in the future. Perhaps a tragic ending is more natural, as in the case of the Cavendish banana.
The movie opens with a quote from the Bible, Ecclesiastes 7:13. “Consider God’s handiwork; who can straighten what He hath made crooked?” In other words, crooked means what it says. Our genetic information is the result of a long evolutionary process of natural selection, and as such, it stands on its own and should not be altered. Changes in the environment have already caused the extinction of many creatures besides bananas. We should always keep in mind that we could be next.