Point mutation

From WikiMD

Illustration of three types of point mutations.

A point mutation is a single base substitution.[1] It is the smallest type of mutation possible.

In a point mutation, either:

  1. a single base nucleotide is changed for another nucleotide of the genetic material (normally DNA),[2] or
  2. a single base pair is inserted or deleted.[3]

A nonsense mutation is a point mutation in a DNA sequence that leads to an early stop codon.[4] This appears as a nonsense codon in the transcribed mRNA. Most of the time, the protein that is translated from this mRNA does not work.


  1. Eldon D Enger; Frederick C Ross; David B Bailey, Concepts in Biology, 12th Edition (London: McGraw-Hill, 2007), p. 158

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