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TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Biology > Gene Mutation

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Define Gene Mutation

A change in the base sequence of a gene.

Outline the difference between an insertion and a deletion

Explain the consequence of a base substitution mutation in relation to the process of transcription and translation, using the example of sickle cell anaemia

Base substitutions (aka point mutations) occur when 1 base on a DNA strand is replaced with a different one. This can affect the resulting protein in various ways. Great distortions can arise because during transcription and translation, the DNA that is being read is wrong, and thus do not correctly produce a needed protein. An incorrect sequence of amino acids may alter the shape of the protein, the most important characteristic that defines a protein's function. In the case of sickle cell anaemia, the haemoglobin molecule is crystalline and makes the red blood cell crescent-shaped. Even a slight change in the sequence may be enough to completely alter the information.

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