Gene-centered view of evolution

Changes elsewhere – in the egg cytoplasm, in materials transmitted through the placenta, in the mother's milk – might alter the development of the child, but, unless the changes were in nucleic acids, they would have no long-term evolutionary effects.The rejection of the inheritance of acquired characters, combined with Ronald Fisher the statistician, giving the subject a mathematical footing, and showing how Mendelian genetics was compatible with natural selection in his 1930 book The Genetical Theory of Natural Selection.

[clarification needed] The view of the gene as the unit of selection was developed mainly in the works of Richard Dawkins,[10][11] W. D. Hamilton,[12][13][14] Colin Pittendrigh[15] and George C.

So, a particular gene coded in a nucleobase sequence of a lineage of replicated DNA molecules can have a high permanence and a low rate of endogenous change.

[17] In normal sexual reproduction, an entire genome is the unique combination of father's and mother's chromosomes produced at the moment of fertilization.

And the high prevalence of horizontal gene transfer in bacteria and archaea means that genomic combinations of these asexually reproducing groups are also transient in evolutionary time: "The traditional view, that prokaryotic evolution can be understood primarily in terms of clonal divergence and periodic selection, must be augmented to embrace gene exchange as a creative force.

"[18][19] The gene as an informational entity persists for an evolutionarily significant span of time through a lineage of many physical copies.

[2][20] In his book River out of Eden, Dawkins coins the phrase God's utility function to explain his view on genes as units of selection.

[note 1] An adaptation is maintained by selection if it promotes genetic survival directly, or else some subordinate goal that ultimately contributes to successful reproduction.

Actions with substantial costs therefore require significant values of p. Two kinds of factors ensure high values of p: relatedness (kinship) and recognition (green beards).A gene in a somatic cell of an individual may forgo replication to promote the transmission of its copies in the germ line cells.

The kin selection theory predicts that a gene may promote the recognition of kinship by historical continuity: a mammalian mother learns to identify her own offspring in the act of giving birth; a male preferentially directs resources to the offspring of mothers with whom he has copulated; the other chicks in a nest are siblings; and so on.

"[26] However, examining the human propensity for altruism, kin selection theory seems incapable of explaining cross-familiar, cross-racial and even cross-species acts of kindness, to which Richard Dawkins wrote: Lay critics frequently bring up some apparently maladaptive feature of modern human behaviour—adoption, say, or contraception [...] The question, about the adaptive significance of behaviour in an artificial world, should never have been put [...] A useful analogy here is one that I heard from R. D. Alexander.

If we had characterized the behaviour differently and asked ‘Why do moths maintain a fixed angle to light rays (a habit which incidentally causes them to spiral into the light source if the rays happen not to be parallel)?’, we should not have been so puzzled.Green-beard effects gained their name from a thought-experiment first presented by Bill Hamilton[27] and then popularized and given its current name by Richard Dawkins who considered the possibility of a gene that caused its possessors to develop a green beard and to be nice to other green-bearded individuals.

Since then, green-beard genes have been discovered in nature, such as Gp-9 in fire ants (Solenopsis invicta),[28][29] csA in social amoeba (Dictyostelium discoideum),[30] and FLO1 in budding yeast (Saccharomyces cerevisiae).

The classic example is segregation distorter genes that cheat during meiosis or gametogenesis and end up in more than half of the functional gametes.

Besides Richard Dawkins and George C. Williams, other biologists and philosophers have expanded and refined the selfish-gene theory, such as John Maynard Smith, George R. Price, Robert Trivers, David Haig, Helena Cronin, David Hull, Philip Kitcher, and Daniel C. Dennett.

The gene-centric view has been opposed by Ernst Mayr, Stephen Jay Gould, David Sloan Wilson, and philosopher Elliott Sober.

Gould also called the claims of Selfish Gene "strict adaptationism", "ultra-Darwinism", and "Darwinian fundamentalism", describing them as excessively "reductionist".

[36] Gould acknowledged that Dawkins was not imputing conscious action to genes, but simply using a shorthand metaphor commonly found in evolutionary writings.

To Gould, the fatal flaw was that "no matter how much power Dawkins wishes to assign to genes, there is one thing that he cannot give them – direct visibility to natural selection.