Insertion-deletion mutation

In the Menkes disease gene, approximately 20% of the mutations are insertion/deletion mutation of varying sizes. In a study of 41 umelated patients presenting the severe form of Menkes disease, 19 mutations were due to insertion or deletion. The two largest of the deletions are 14 bp deletion in exon 10 and 10 bp deletion in exon 22. These deletions, as... 

The small insertion/deletion mutations account for about 23% of the nucleic acid sequence alterations that cause disease. An insertion refers to the presence of extra bases while deletion implies the absence of certain bases in comparison to a reference sequence. Insertion and deletion mutations often result in a shift of the codon reading frame, resulting in altered amino acid sequence downstream of the mutation—commonly followed by chain termination from a nonsense codon. Indels are deletions followed by insertions (e.g., replacement of AGGTC by TG). 

Fujii, R., Kitaoka, M. and Hayashi, K., RAISE a simple and novel method of generating random insertion and deletion mutations. Nucleic Acids Res., 2006, 34, 30. 

The best way to illustrate the importance of DNA repair is to consider the effects of unrepaired DNA damage (a lesion). The most serious outcome is a change in the base sequence of the DNA, which, if replicated and transmitted to future cell generations, becomes permanent. A permanent change in the nucleotide sequence of DNA is called a mutation. Mutations can involve the replacement of one base pair with another (substitution mutation) or the addition or deletion of one or more base pairs (insertion or deletion mutations). If the mutation affects nonessential DNA or if it has a negligible... 

Fig. 14. Examples of homogeneous hybridization assay methods (F luminophore, Q quencher, D donor, A acceptor). Thick lines represent DNA strands. Open circles on DNA strands indicate a SNP/mutation site for Molecular Beacon and insertion/deletion sites for dual FRET probe and dual FRET Molecular Beacon when these methods are applied to SNP/mutation typing or deletion/insertion detection. The solid circle on die strand indicates the complementary site.

Resistance develops due to the ability of DNA to 1) undergo spontaneous mutation, or 2) move from one organism to another. In the first instance, chromosomal alteration may occur by insertion, deletion or substitution of one or more nucleotides within the genome1. 

The 12 possible types of nucleotide substitution can be treated differently (assuming nonsymmetry of change, e.g., the frequency of A to C does not equal that for C to A) or treated equally, or any combination of these substitutions can be grouped. One obvious division of base substitutions is to treat transitions (changes of purine to purine or pyrimidine to pyrimidine) separately from transversions (change of purine to pyrimidine or vice versa). Insertion/deletion events can also be treated as a separate type of mutation. Additionally, nucleotide substitutions can be preferentially treated by a combination of position and mutation (e.g., transversions occurring in the first and second codon positions). 

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