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Adaptive mutation, also called directed mutation or directed mutagenesis is a controversial evolutionary theory. It posits that mutations, or genetic changes, are much less random and more purposeful than traditional evolution, implying that organisms can respond to environmental stresses by directing mutations to certain genes or areas of the genome.
Mutations that are not deleterious are assumed to be mostly neutral rather than beneficial. [31] The theory was controversial as it sounded like a challenge to Darwinian evolution; controversy was intensified by a 1969 paper by Jack Lester King and Thomas H. Jukes, provocatively but misleadingly titled "Non-Darwinian Evolution".
Alternatively, the adaptive mutations may be the ones which reduce the chance of disease arising due to other mutations. However, this second explanation seems unlikely, because the mutation rate in the human genome is fairly low, so selection would be relatively weak. Immune genes
Adaptation is an observable fact of life accepted by philosophers and natural historians from ancient times, independently of their views on evolution, but their explanations differed. Empedocles did not believe that adaptation required a final cause (a purpose), but thought that it "came about naturally, since such things survived."
In the theory, mutation was the source of novelty, creating new forms and new species, potentially instantaneously, [1] in sudden jumps. [2] This was envisaged as driving evolution, which was thought to be limited by the supply of mutations.
Today, evolutionary biologists try to determine the genetic architecture underlying visible evolutionary phenomena such as adaptation and speciation. They seek answers to questions such as which genes are involved, how interdependent are the effects of different genes, what do the genes do, and what changes happen to them (e.g., point mutations ...
Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought is a 1966 book by the American evolutionary biologist George C. Williams.Williams, in what is now considered a classic by evolutionary biologists, [1] outlines a gene-centered view of evolution, [2] disputes notions of evolutionary progress, and criticizes contemporary models of group selection, including the ...
The neutral theory holds that as functional constraint diminishes, the probability that a mutation is neutral rises, and so should the rate of sequence divergence. When comparing various proteins , extremely high evolutionary rates were observed in proteins such as fibrinopeptides and the C chain of the proinsulin molecule, which both have ...