<P> The selfish - gene theory of natural selection can be restated as follows: </P> <P> Genes do not present themselves naked to the scrutiny of natural selection, instead they present their phenotypic effects . (...) Differences in genes give rise to differences in these phenotypic effects . Natural selection acts on the phenotypic differences and thereby on genes . Thus genes come to be represented in successive generations in proportion to the selective value of their phenotypic effects . </P> <P> The result is that "the prevalent genes in a sexual population must be those that, as a mean condition, through a large number of genotypes in a large number of situations, have had the most favourable phenotypic effects for their own replication ." In other words, we expect selfish genes ("selfish" meaning that it promotes its own survival without necessarily promoting the survival of the organism, group or even species). This theory implies that adaptations are the phenotypic effects of genes to maximize their representation in future generations . An adaptation is maintained by selection if it promotes genetic survival directly, or else some subordinate goal that ultimately contributes to successful reproduction . </P> <P> The gene is a unit of hereditary information that exists in many physical copies in the world, and which particular physical copy will be replicated and originate new copies does not matter from the gene's point of view . A selfish gene could be favored by selection by producing altruism among organisms containing it . The idea is summarized as follows: </P>

The chances of a gene replicating itself is enhanced if