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Silent mutation

 

 
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Silent mutation
 
 
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Silent mutations are DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 mutation
Mutation

In biology, mutations are changes to the nucleotide sequence of the genetic material of an organism. Mutations can be caused by copying errors in the genetic material during cell division, by exposure to ultraviolet or ionizing radiation, chemical mutagens, or virus , or can be induced by the organism, itself, by cellular processes such as s...
s that do not result in a change to the amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
 sequence of a protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
. They may occur in a non-coding region
Noncoding DNA

In genetics, non-coding DNA describes DNA which does not contain genetic code for making proteins . In eukaryotes, a large percentage of many organisms' total genome sizes is comprised of noncoding DNA ....
 (outside of a gene
Gene

A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cell and pass genetic trait to offspring....
 or within an intron
Intron

Introns, derived from the term "intragenic regions" and also called intervening sequence , are DNA regions in a gene that are not translated into proteins....
), or they may occur within an exon
Exon

An exon in a gene is a DNA or RNA sequence that is translated into RNA or protein. In contrast, an intron is a DNA sequence in the gene that is not translated....
 in a manner that does not alter the final amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
 sequence. The phrase silent mutation is often used interchangeably with the phrase synonymous mutation; however, synonymous mutations are a subcategory of the former, occurring only within exons.

Because silent mutations do not alter protein function they are often treated as though they are evolutionarily neutral
Neutral theory of molecular evolution

The neutral theory of molecular evolution is an influential theory that was introduced with provocative effect by Motoo Kimura in the late 1960s and early 1970s, which states that the vast majority of evolutionary changes at the molecular level are caused by random drift of selectively neutral mutants....
.






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Encyclopedia


Silent mutations are DNA
DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetics instructions used in the development and functioning of all known living organisms and some viruses....
 mutation
Mutation

In biology, mutations are changes to the nucleotide sequence of the genetic material of an organism. Mutations can be caused by copying errors in the genetic material during cell division, by exposure to ultraviolet or ionizing radiation, chemical mutagens, or virus , or can be induced by the organism, itself, by cellular processes such as s...
s that do not result in a change to the amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
 sequence of a protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
. They may occur in a non-coding region
Noncoding DNA

In genetics, non-coding DNA describes DNA which does not contain genetic code for making proteins . In eukaryotes, a large percentage of many organisms' total genome sizes is comprised of noncoding DNA ....
 (outside of a gene
Gene

A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cell and pass genetic trait to offspring....
 or within an intron
Intron

Introns, derived from the term "intragenic regions" and also called intervening sequence , are DNA regions in a gene that are not translated into proteins....
), or they may occur within an exon
Exon

An exon in a gene is a DNA or RNA sequence that is translated into RNA or protein. In contrast, an intron is a DNA sequence in the gene that is not translated....
 in a manner that does not alter the final amino acid
Amino acid

In chemistry, an amino acid is a molecule containing both amine and carboxyl functional groups. These molecules are particularly important in biochemistry, where this term refers to alpha-amino acids with the general formula H2NCHRCOOH, where R is an organic substituent....
 sequence. The phrase silent mutation is often used interchangeably with the phrase synonymous mutation; however, synonymous mutations are a subcategory of the former, occurring only within exons.

Because silent mutations do not alter protein function they are often treated as though they are evolutionarily neutral
Neutral theory of molecular evolution

The neutral theory of molecular evolution is an influential theory that was introduced with provocative effect by Motoo Kimura in the late 1960s and early 1970s, which states that the vast majority of evolutionary changes at the molecular level are caused by random drift of selectively neutral mutants....
. However, many organisms are known to exhibit codon usage bias
Codon usage bias

Codon usage bias refers to differences among organisms in the frequency of occurrence of codons in protein-coding DNA sequences . A codon is a series of three nucleotides that Genetic codes a specific amino acid residue in a polypeptide chain....
es, suggesting that there is selection
Natural selection

Natural selection is the process by which favorable heritable trait become more common in successive generations of a population of Reproduction organisms, and unfavorable heritable traits become less common, due to differential reproduction of genotypes....
 for the use of particular codons due to translational stability. Silent mutations may also affect splicing
Splicing (genetics)

In molecular biology, splicing is a modification of an RNA after transcription , in which introns are removed and exons are joined. This is needed for the typical eukaryotic messenger RNA before it can be used to produce a correct protein through translation ....
, or transcriptional control
Transcription (genetics)

Transcription is the synthesis of RNA under the direction of DNA. RNA synthesis, or transcription, is the process of transcribing DNA nucleotide sequence information into RNA sequence information....
.

In molecular cloning experiments, it can be useful to introduce silent mutations into a gene of interest in order to create or remove recognition sites for restriction enzymes. An online tool that can analyse a sequence of interest for possible mutations to create restriction sites is given in the External Links section.

Recent results suggest that silent mutations can have an effect on subsequent protein structure and activity,.

See also

  • Degeneracy of the genetic code
    Genetic code

    The genetic code is the set of rules by which information encoded in genetic material is Translation into proteins by living cell s. The code defines a mapping between tri-nucleotide sequences, called codons, and amino acids....
  • Genealogical DNA test
    Genealogical DNA test

    A genealogical DNA test examines the nucleotides at specific locations on a person's DNA for genetic genealogy purposes. The test results are not meant to have any informative medical value and do not determine specific genetic diseases or disorders ; they are intended only to give genealogical information....


External links