Selfish gene

A selfish gene is a stretch of DNA that propagates itself through populations by promoting the survival and reproduction of the vehicles — organisms — that carry it, even when the gene's effects are detrimental to the organism or to other genes in the same genome. The concept, introduced by Richard Dawkins in his 1976 book The Selfish Gene, inverts the traditional organism-centered view of natural selection: selection operates on genes, and organisms are merely the temporary survival machines that genes build and discard. The selfish gene perspective explains a wide range of biological phenomena — from altruistic behavior in kin to the persistence of deleterious genetic elements — that are puzzling from an organism-centered framework.

The concept is controversial not because it is false but because it is partial. Genes do compete, but they also cooperate: the genome is not a battlefield of selfish actors but a coalition of interdependent elements whose fitness depends on the fitness of the whole. A complete theory of evolution requires not the gene-centered view alone but a multi-level framework in which selection operates simultaneously on genes, organisms, and groups.