The Selfish Gene

selfish gene

The Selfish Gene is a book on evolution by Richard Dawkins, published in 1976. It builds upon the principal theory of George C. Williams’s first book ‘Adaptation and Natural Selection.’ Dawkins coined the term ‘selfish gene’ as a way of expressing the gene-centred view of evolution as opposed to the views focused on the organism and the group. From the gene-centred view follows that the more two individuals are genetically related, the more sense (at the level of the genes) it makes for them to behave selflessly with each other. Therefore the concept is especially good at explaining many forms of altruism, regardless of a common misuse of the term along the lines of a selfishness gene.

An organism is expected to evolve to maximize its inclusive fitness — the number of copies of its genes passed on globally (rather than by a particular individual). As a result, populations will tend towards an evolutionarily stable strategy. The book also coins the term ‘meme’ for a unit of human cultural evolution analogous to the gene, suggesting that such ‘selfish’ replication may also model human culture, in a different sense. Memetics has become the subject of many studies since the publication of the book.

In describing genes as being ‘selfish,’ the author does not intend (as he states unequivocally in the work) to imply that they are driven by any motives or will — merely that their effects can be accurately described as if they were. The contention is that the genes that get passed on are the ones whose consequences serve their own implicit interests (to continue being replicated), not necessarily those of the organism, much less any larger level.

Dawkins proposes the idea of the ‘replicator,’ the initial molecule which first managed to reproduce itself and thus gained an advantage over other molecules within the primordial soup. Today, Dawkins postulates, the replicators are the genes within organisms, with each organism’s body serving the purpose of a ‘survival machine’ for its genes.

Dawkins writes that gene combinations which help an organism to survive and reproduce tend to also improve the gene’s own chances of being passed on and, as a result, frequently ‘successful’ genes will also be beneficial to the organism. An example of this might be a gene that protects the organism against a disease, which helps the gene spread and also helps the organism.

There are other times when the implicit interests of the vehicle and replicator are in conflict, such as the genes behind certain male spiders’ instinctive mating behavior, which increase the organism’s inclusive fitness by allowing it to reproduce, but shorten its life by exposing it to the risk of being eaten by the cannibalistic female. Another good example is the existence of segregation distortion genes that are detrimental to their host but nonetheless propagate themselves at its expense. Likewise, the existence of junk DNA that provides no benefit to its host, once a puzzle, can be more easily explained.

These examples might suggest that there is a power-struggle between genes and their host. In fact, the claim is that there isn’t much of a struggle because the genes usually win without a fight. Only if the organism becomes intelligent enough to understand its own interests, as distinct from those of its genes, can there be true conflict. An example of this conflict might be a person using birth control to prevent fertilization and thereby inhibit the replication of his or her genes.

But that may not be a conflict of the ‘self-interest’ of the organism with his or her genes since a person using birth control may also be enhancing the survival chances of his or her genes by limiting his or her family size to conform with available resources thus avoiding extinction by uncontrolled population growth.

When examined from the standpoint of gene selection, many biological phenomena that, in prior models, were difficult to explain become easier to understand. In particular, phenomena such as kin selection and eusociality (caste systems like bees have), where organisms act altruistically, against their individual interests (in the sense of health, safety or personal reproduction) to help related organisms reproduce, can be explained as gene sets ‘helping’ copies of themselves in other bodies to replicate. Interestingly, the ‘selfish’ actions of genes lead to unselfish actions by organisms.

Most modern evolutionary biologists accept that the idea is consistent with many processes in evolution. However, the view that selection on other levels, such as organisms and populations, seldom opposes selection on genes is more controversial.

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