Gene mutation

A gene mutation is a change in one or several bases. A base may be added, deleted, or substituted with another base. This is caused often through the action of damaging chemicals, radiations, or through errors inherent in DNA replication and repair reactions. If a base is added or deleted, frameshift is the result as a different amino acid is coded for. As the sequence of amino acids is altered, a non-functional protein may be produced. However, in some cases, mutations do not affect the amino acid coded for. This is because the mutation may occur in a non-coding region of the DNA. The genetic code is also degenerate as more than one codon may code for a certain amino acid. Finally, the amino acid may be in a non-essential position of the polypeptide, hence its 3 dimensional structure is not significantly altered.