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Types of Mutations: Substitution, Insertions, Deletion and Frameshifts
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This is a very informative post. I would just like to make a few clarifications and additions to help students coming to get information.


There are three types of base-substitution mutations. As the original poster noted, when a base substitution mutation does not change the amino acid inserted into the gene, it is called a “silent mutation.” When the base substitution does change the amino acid, this is called a “missense mutation.” When the substitution results in a stop codon being inserted, this is called a “nonsense mutation.” I remember this by thinking that “nonsense” is similar to saying “no more”, so the protein is ended.


Insertion and deletion mutations can result in frameshift mutations, when the reading frame of the gene is changed. This frameshift only happens when the insertion or mutation is not a multiple of 3 nucleotides. For example, look at the sentence:

The big red pig ate the ham.


If we insert 2 letters, the frame is shifted.

The big rec adp iga tet heh am.


If we insert 3 letters, the frame is not shifted; however, an extra amino acid is added, which changes the sentence.

The big red cat pig ate the ham.


Insertion and deletion mutations can be as small as one nucleotide, to thousands of nucleotides long. These long insertion or deletion mutations normally occur when one part of a chromosome crosses over and changes genetic information with a different chromosome.


All mutations have the potential to be very damaging, but most are benign. Mutations are an important part of evolution, allowing us to develop adaptations and diversity.
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RE: Types of Mutations: Substitution, Insertions, Deletion and Frameshifts - by bridgettpayseur - 08-09-2013, 12:41 AM



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