Prominent NAS member trashes neo-Darwinism
|July 18, 2007||Posted by scordova under Darwinism, Science|
Natural selection …is not the fundamental cause of evolution.
Science continues to destroy Darwinism. A prominent member of the National Academy of Sciences, Masatoshi Nei, trashed neo-Darwinism in the recent peer-reviewed article: The new mutation theory of phenotypic evolution.
Haldane’s dilemma showed mathematically that natural selection could not be the major driving force of evolution. Haldane’s dilemma lead in part to the non-Darwinian theory of molecular evolution known as the “neutral theory of molecular evolution”. Neutral theory asserted natural selection was not the principal driving force of molecular evolution. However, when molecular neutral theory was presented to the world in the 1960’s, it was politically incorrect to assert the obvious consequence of the neutral theory of molecular evolution, namely: morphology, physiology, and practically anything else made of molecules would NOT be principally shaped by natural selection either.
In What are the speed limits of naturalistic evolution?, I pointed out:
And if Haldane’s dilemma were not enough of a blow to Darwinian evolution, in the 1960’s several population geneticists like Motoo Kimura demonstrated mathematically that the overwhelming majority of molecular evolution was non-Darwinian and invisible to natural selection. Lest he be found guilty for blasphemy, Kimura made an obligatory salute to Darwin by saying his non-Darwinian neutral theory “does not deny the role of natural selection in determining the course of adaptive evolution”. That’s right, according to Kimura, adaptive evolution is visible to natural selection while simultaneously molecular evolution is invisible to natural selection. Is such a position logical? No. Is it politically and intellectually expedient? Absolutely!
But now 4 decades later, the inevitable consequence of Haldane’s dilemma and Kimura’s neutral theory may be ending the uneasy truce between neo-Darwinists and neutralists.
For the last six decades, the dominant theory of evolution has been neo-Darwinism, which was developed by the three founders of theoretical population genetics, Fisher (1), Wright (2), and Haldane (3), and was later supported by various evolutionists (4). Neo-Darwinism asserts that natural selection is the driving force of evolution,
In the last four decades, the study of molecular evolution has shown that a majority of amino acid substitutions in proteins are neutral or nearly neutral
However, most evolutionists still believe in neo-Darwinism with respect to phenotypic evolution and are not interested in neutral evolution (19,22).
Mayr (23) stated that neutral mutations apparently occur at the molecular level, but because they do not affect phenotypic characters, they are of little interest to evolutionists.
By contrast, Nei (17, 24, 25) argued that because phenotypic characters are ultimately controlled by DNA sequences, both molecular and phenotypic evolution must occur in similar [non Darwinian] ways. He also suggested that a considerable portion of morphological evolution is caused by neutral or nearly neutral mutations, and the driving force of evolution is mutation at both molecular and phenotypic levels.
As mentioned in the introduction, a majority of current evolutionists believe in neo-Darwinism. In one of the most popular textbooks on evolution, Futuyma (ref. 20, p. 10) states that evolutionary change is a population process in which one genotype replaces other ones, and for this process to occur, mutation is quite ineffective because of its low rate of occurrence, whereas even the slightest intensity of natural selection can bring about substantial change in a realistic amount of time. He also states “Natural selection can account for both slight and great differences among species, and adaptations are traits that have been shaped by natural selection.” Although this type of statement is quite common in the evolutionary literature, it is obvious that any advantageous genotype is produced by mutation including all kinds of genetic changes. Natural selection occurs as a consequence of mutational production of different genotypes, and therefore it is not the fundamental cause of evolution.
Historically, the word mutationism was used to refer to William Bateson’s saltationism or similar ideas, in which natural selection plays little role. Later Morgan (109) presented a more reasonable form of mutationism taking into account the role of natural selection. His view was abstract and based on a few lines of speculative arguments. However, recent molecular studies of phenotypic evolution support the basic ideas of his view and have extended it to a more comprehensive view presented in this article. If the new form of mutation theory described here is right, even in its crudest form, more emphasis should be given on the roles of mutation in the study of evolution.
1. ID sympathizer Dr. John Davison, who has spent much of his recent life promoting the works of William Bateson, should be much encouraged with these developments. It was through Davison I learned of Bateson’s wonderful ideas.
2. Richard Dawkins wrote of Kimura in Blindwatchmaker. Dawkins argued Kimura’s ideas wouldn’t overturn Darwinism since Darwinism operated at the higher level of adaptation whereas Kimura’s non-Darwinian theory operated at the lower level of molecules. But the reductionists are now getting taste of their own medicine. If the Darwinism doesn’t operate at the molecular level, then why should we expect it to operate at much higher levels like morphology and physiology either?
3. Lewontin gives a powerful example of neutral evolution at the morphological level. Rhinos have either 1 horn or 2 horns. Did natural selection cause the evolution of one horn in one case, and 2 horns in another? Unlikely.
4. Salthe pointed out a fundamental contradiction in Fisher’s fundamental theorem of natural selection. Selection is the enemy of diversity. Salthe realized the obvious problem of trying to account for the abundance of diversity through a mechanism which reduces diversity.
5. At least 3 signatories of the Discovery Institute’s Dissent from Darwin list anticipated these recent developments. Davison, Salthe, and Ho. Ho managed to present echoes of these ideas 30 years ago in a peer-reviewed journal. See: An eloquent but bogus non-review by Dawkins.
a relative lack of natural selection may be the prerequisite for major evolutionary advance
Mae Wan Ho