Base substitutions are the simplest type of gene-level mutation, and they involve the swapping of one nucleotide for another during DNA replication. For example, during replication, a thymine nucleotide might be inserted in place of a guanine nucleotide.

What is an example of a substitution mutation?

Substitution mutations are a type of mutation in which a single nucleotide is substituted with a different nucleotide. Examples of (base-pair) substitutions: a purine is substituted with a different purine (A → G) or a pyrimidine, for a different pyrimidine (C → T).

What causes base pair substitution?

A type of mutation involving replacement or substitution of a single nucleotide base with another in DNA or RNA molecule. This type of mutation occurring in noncoding sequences often does not result in an altered amino acid sequence during translation.