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Silent mutations, also called synonymous or samesense mutations, are mutations in DNA that do not have an observable effect on the organism's phenotype. The phrase silent mutation is often used interchangeably with the phrase synonymous mutation ; however, synonymous mutations are not always silent, nor vice versa.
Point substitution mutations of a codon, classified by their impact on protein sequence. A synonymous substitution (often called a silent substitution though they are not always silent) is the evolutionary substitution of one base for another in an exon of a gene coding for a protein, such that the produced amino acid sequence is not modified.
A nonsynonymous substitution is a nucleotide mutation that alters the amino acid sequence of a protein.Nonsynonymous substitutions differ from synonymous substitutions, which do not alter amino acid sequences and are (sometimes) silent mutations.
The genetic differences among divergent populations can involve silent mutations (that have no effect on the phenotype) or give rise to significant morphological and/or physiological changes. Genetic divergence will always accompany reproductive isolation, either due to novel adaptations via selection and/or due to genetic drift, and is the ...
For example, silent mutations that do not change the corresponding amino acid sequence of a gene may change the frequency of guanine-cytosine base pairs . These base pairs have a higher thermal stability ( melting point ) than adenine - thymine , a property that might convey, among organisms living in high-temperature environments, a selective ...
Sociobiology is a field of biology that aims to explain social behavior in terms of evolution.It draws from disciplines including psychology, ethology, anthropology, evolution, zoology, archaeology, and population genetics.
The neutrality index (NI) quantifies the direction and degree of departure from neutrality (where P n /P s and D n /D s ratios are equal). When assuming that silent mutations are neutral, a neutrality index greater than 1 (i.e. NI > 1) indicates negative selection is at work, resulting in an excess of amino acid polymorphism.
A 2022 study reported that synonymous mutations in representative yeast genes are mostly strongly non-neutral, which calls into question the assumptions underlying use of the K a /K s ratio. [ 4 ] In addition, as time progresses, it is possible for a site to undergo multiple modifications.