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Neutral mutation has become a part of the neutral theory of molecular evolution, proposed in the 1960s. This theory suggests that neutral mutations are responsible for a large portion of DNA sequence changes in a species. For example, bovine and human insulin, while differing in amino acid sequence are still able to perform the same function ...
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 ...
The Neutral Theory of Molecular Evolution is an influential monograph written in 1983 by Japanese evolutionary biologist Motoo Kimura.While the neutral theory of molecular evolution existed since his article in 1968, [1] Kimura felt the need to write a monograph with up-to-date information and evidences showing the importance of his theory in evolution.
The neutral theory allows for the possibility that most mutations are deleterious, but holds that because these are rapidly purged by natural selection, they do not make significant contributions to variation within and between species at the molecular level. Mutations that are not deleterious are assumed to be mostly neutral rather than ...
A beneficial, or advantageous mutation increases the fitness of the organism. Examples are mutations that lead to antibiotic resistance in bacteria (which are beneficial for bacteria but usually not for humans). A neutral mutation has no harmful or beneficial effect on the organism.
The paper brings together a wide variety of evidence, ranging from protein sequence comparisons to studies of the Treffers mutator gene [1] in E. coli to analysis of the genetic code to comparative immunology, to argue that most protein evolution is due to neutral mutations and genetic drift. It was published in the journal Science on May 16 ...
For a diploid population of size N and neutral mutation rate, the initial frequency of a novel mutation is simply 1/(2N), and the number of new mutations per generation is . Since the fixation rate is the rate of novel neutral mutation multiplied by their probability of fixation, the overall fixation rate is 2 N μ × 1 2 N = μ {\displaystyle ...
For neutral mutations, the rate of fixation per generation is equal to the mutation rate per replication. A relatively constant mutation rate thus produces a constant rate of change per generation (molecular clock). Slightly deleterious mutations with a selection coefficient less than a threshold value of 1 / the effective population size can ...