In this blog post, we will look at whether genes are a selfish strategy for survival or a product of evolutionary adaptation to environmental change.
Richard Dawkins’ book “The Selfish Gene” has a provocative title. Since humans have been taught to respect and care for others as virtues, the idea that genes that contain all our information are selfish seems to support the idea that humans are inherently evil and that we must learn good through education. However, perhaps because of this provocation, “The Selfish Gene” became one of the most widely read science popular books in the world, and many people agreed with the claims made by its author, Richard Dawkins.
In fact, when the book was first published, many people were strongly opposed to the title. The word “selfish” is usually used in a negative sense, and people instinctively take it negatively. However, as people read Dawkins’ book, they gradually came to understand that the concept of selfishness is simply a separate issue from moral judgment. The expression “selfish” was used to describe how the biological unit of genes acts for its own survival, and it does not itself represent the ethical tendencies of humans. For this reason, many readers have come to sympathize with Dawkins’ point of view, beyond their initial antipathy.
Unlike the antipathy that the title may arouse, the reason why many people could agree with it is probably because Dawkins emphasizes the need to view evolution and behavior from the perspective of genes, that is, from the perspective of what benefits and damages each gene. In addition, this book does not simply deal with the concept of selfish genes, but also provides new insights into the role of genes in the process of biological evolution and natural selection. He explained that genes have a strategy to “preserve” and “expand” themselves, offering readers a new perspective on understanding the theory of evolution.
So, from the perspective of genes, how did sexual reproduction come about? Before continuing the discussion, we should first look at what genes are. The gene is a very popular and widely known scientific term, but there is a lot of controversy and confusion about its definition. The concepts of genes among scientists are largely divided into molecular and evolutionary concepts. In the molecular concept, genes are defined as DNA strands that encode proteins. Generally, when we talk about DNA strands that encode proteins, we are referring to exons and regulatory sites that control gene expression, excluding introns that are lost during the editing process. However, in order for a protein to be produced, various other RNA and environmental factors are involved, making it ambiguous to refer to what is a gene.
Genes are not only biological structures, but can also be seen as elements that are affected by natural selection during the process of evolution. For this reason, Dawkins emphasizes that genes should be understood as evolutionary concepts that take into account their influence and role, rather than simply being defined at the molecular level. The evolutionary concept is a concept that has emerged to replace this. In the evolutionary concept, genes are defined as DNA sequences that cause differences in phenotypes. In other words, if the phenotype changes when a specific DNA sequence is replaced with another DNA sequence, then that sequence is a gene. Of these two definitions, Dawkins argues that the definition of the evolutionary concept should be used. Therefore, if genes that exhibit similar traits through mutations such as inversion are located in close physical proximity, they can be grouped together and referred to as a new gene.
In addition, the lifespan of a gene refers to the time it can be passed on intact through generations, so the shorter the length of a gene, the longer its lifespan, as the probability of the gene being cut off by crossing during meiosis is reduced. This can be understood as part of the complexity of genes and their survival strategies. Short genes have more chances of survival, so they can survive for a longer period of time in the process of evolution.
According to the selfish gene theory, the goal of genes is to ensure the survival of themselves or their clones. Then why do organisms reproduce sexually rather than asexually, which would leave them unchanged? In response, Dawkins argues that sexual reproduction itself is just a trait controlled by a single gene, and that it does not matter whether sexual reproduction is beneficial to all of the remaining genes in the individual. They say that sexual reproduction has spread throughout the gene pool because it is beneficial to the genes that enable sexual reproduction. The gene pool is the total amount of genetic information contained in a group of organisms, and it can be thought of as a collection of all the alleles possessed by the individuals in the group.
If a population is evolutionarily stable, the proportion of genes that make up this gene pool will remain constant. Therefore, if a gene survives and spreads in the gene pool, it means that the gene is evolutionarily stable and can leave its own replicators to future generations. However, Dawkins avoids mentioning how sexual reproduction is beneficial to sexual reproduction genes. Therefore, in this article, I would like to present how sexual reproduction could have survived in the gene pool based on Dawkins’ argument.
To examine whether Dawkins’s claim is correct, we need to consider whether the process of “evolution” can occur, in which a sexual reproduction gene appears in the gene pool where asexual reproduction genes exist, and this sexual reproduction gene goes through a transitional stage without being eliminated to form a new gene pool. However, asexual reproduction does not require the cumbersome process of finding a mate during the reproduction process, and since no crossbreeding occurs, the lifespan of the genes can be considered almost infinite. From this perspective, it seems that sexual reproduction genes will be eliminated from the gene pool.
So, is there a reason why sexual reproduction genes can survive despite the advantages of asexual reproduction? The advantage of sexual reproduction, which is often taught in the curriculum, is that it creates individuals with new traits through a combination of various genes, and based on this, better genetic traits are passed on to the species, thereby increasing the probability of the species’ survival. This is the advantage of sexual reproduction from a species perspective. From this perspective, and from the perspective of genes, we can speculate on some interesting reasons why sexual reproduction is beneficial to genes.
First, when sexual reproduction occurs, the offspring will have relatives with genetic kinship. These relatives are more likely to behave altruistically due to their genetic kinship, and therefore the probability of the offspring’s survival increases. The survival of the offspring is directly linked to the survival of the individual with its own genes. In other words, it creates allies to protect its own genes.
There are also cases where the benefits from a species perspective become the benefits from a gene perspective. This is when environmental changes occur that put the species at risk of extinction. When both sexual and asexual reproduction genes exist within the same gene pool, if a rapid environmental change occurs, the asexual reproduction genes will not be able to guarantee the survival of the individuals that carry them, and as a result, they will not be passed on to future generations. On the other hand, individuals with sex-reproduction genes will express various traits due to the mixing of genes, and as a result, there will be individuals that survive. As a result, the genes that remain in the gene pool are sex-reproduction genes. In fact, individuals that reproduce sexually are known to be better able to cope with relatively rapid changes in the environment.
Of course, these explanations are nothing more than hypotheses. However, the reason why Dawkins was able to gain attention with the term “selfish genes” was that he provided a new perspective through the biological concept of genes to explain natural selection and evolution again. After reading this book, you will be able to go beyond simply learning about genetics and understand the role of genes in the larger biological flow and how individual behaviors and traits are formed in the process.
