Having finished ‘The Selfish Gene’ a few months ago, I have finally gotten around to publishing a review. Dawkins coined the term selfish gene as a way of expressing the gene-centred view of evolution, which holds that evolution is best viewed as acting on genes and that selection at the level of organisms or populations almost never overrides selection based on genes. In chapter three, he explains:
“Genes are competing directly with their alleles for survival, since their alleles in the gene pool are rivals for their slot on the chromosomes of future generations. Any gene that behaves in such a way as to increase its own survival chances in the gene pool at the expense of its alleles will, by definition, tautologously, tend to survive. The gene is the basic unit of selfishness.”
This way of looking at selection, from the perspective of the gene, gets extended to such emergent behaviors as kin selection and altruism, by way of the fact that an allele not only gets propogated through the gene pool by helping the immediate organism survive, it also helps other copies of itself survive in other members of its species. Meaning, altruistic behavior is a natural outcome of selection, even if it is bad for the individual organism, because the genes themselves are acting selfishly by protecting other copies of themselves. Dawkins uses numerous clever analogies in order to establish a tangible image of these processes. Of course most genes don’t directly influence behavior, meaning that most genes are, at best, indirectly selfish – but in the case of parochial altruism (within a family or other inbreeding group), most organisms benefiting from altruism likely carry copies of the same non-behavioral genes anyway.
At a time when the idea of group selection was being shown not to be a stable evolutionary strategy, this model provided one way of explaining why kin selection was a much better description of sociality in animals.
For these reasons, The Selfish Gene has rightfully received wide acclaim. But, it is just a metaphor, and no gene is an island. Each gene must act in concert with the rest of an organisms’ genome, which in turn must act to cooperate and compete with other members of its species and within a given ecosystem. As a result, tradeoffs get made. Many times, it is not the allele that is most effective at performing its usual task that is propogated in the gene pool, but the allele that works best with the rest of its genome to generate a successful phenotype that survives.