Question

How does a deletion mutation differ from a substitution mutation?

Answer 1

Mutations are errors in codons that arise due to changes in nucleotide bases.Some mutations will not have a lot of impact. For instance, if the codon GAA becomes the codon GAG, since the genetic code is degenerated, the codon would still code for the amino acid glutamate. However certain mutations may have an enormous influence on the coding of amino acids, which may in turn affect what proteins are made, which may have a significant impact on cellular and organism functioning.

Complete answer:
The most common mutations occur in two ways: 1) A base substitution in which one base is replaced by another; 2) an insertion or deletion in which the base is either wrongly inserted or deleted from the codon.

Base Substitution :
Base substitutions could have a number of effects. The silent mutation is an example of a base substitution, where the change in nucleotide base seems to have no outward effect. Missense mutation refers to base substitution where the change in nucleotide changes the amino acid coded for the affected codon. Nonsense mutation refers to a base substitution in which the transformed nucleotide converts the codon into a stop codon. Such a transition leads to an early termination of translation, which can have a significant impact on the development of proteins.

Deletion Substitution:
When a nucleotide is wrongly added or removed from a codon, the results can be serious. Called a frameshift mutation, insertion or deletion will affect every codon in a specific genetic sequence by throwing out the entire three by three codon structures. In other words, every single codon will code for a new amino acid, resulting in entirely different proteins coded during translation. The physical effects of these mutations are, understandably, generally catastrophic.

Deletion mutation is the deletion of the base from the genetic sequence, which shifts the codon reading frame beyond the mutation stage, rather than the substitution mutation, which involves replacing the base (e.g. one purine) with another base (either purine or pyrimidine). The deletion mutation will lead to frameshift, but the substitution mutation will not.

Note: 1.There is another class of mutations called suppressor mutations.
2.These mutations are "mutations of mutations" that contribute to a new form of change in the genetic code.