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Definition

noun, plural: point mutations

A mutation in DNA or RNA molecule involving a change of only one nucleotide base.

Supplement

This type of mutation occurring in noncoding sequences often does not result in an altered amino acid sequence during translation. If a mutation in the promoter sequence of a gene occurs, the effect may be apparent since the expression of the gene may cause changes in the amino acid sequence, as well as the structure and function of the protein product.

Point mutations may be classified based on functionality:

• nonsense mutation
• missense mutation
• silent mutation

Depending on the type of nitrogenous base involved, this type of mutation may be categorized as:

• transition
• transversion

Sometimes, point mutation also covers mutations caused by single nucleotide insertions or deletions (which are types of frameshift mutation).

Synonym:

• substitution mutation