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a mutation in which a base change or substitution results in a codon that causes insertion of a different amino acid into the growing polypeptide chain, giving rise to an altered protein.
[mis-sense by analogy with non-sense]
missense mutationA base substitution which changes a trinucleotide codon for amino acid “X” into a codon for “Y” corresponding to a different amino acid, which may result in the translation of a non-functioning protein—as occurs in sickle cell anaemia, in which the mutation of a single nucleotide (A to T) on the beta-globin gene results in glutamic acid being substituted by valine at position 6.
A substitution of a single DNA nucleotide for another. This results in the transcription of a different amino acid than is normally found in the protein coded by the gene. Missense mutations are found in diseases such as sickle cell anemia. Red blood cell sickling is caused by the replacement of the amino acid glutamic acid by valine in the sixth position of the beta hemoglobin chain.
See also: mutation