noun, plural: insertion mutations
(genetics) A type of mutation characterized by the insertion of one or few nucleotide base pairs to a chromosome
Mutation is a change in the nucleotide sequence of a gene or a chromosome. Based on the effect of mutation on the gene structure, mutations may be: (1) small-scale mutations or (2) large scale mutations. Small-scale mutations are a type of mutation where one or few nucleotides of a gene are affected. They are further classified as follows: (1) substitution mutations, (2) insertion mutations, and (3) deletion mutations.
Insertion mutations are a type of mutation wherein one or more nucleotide base pairs are inserted to a chromosome or a DNA sequence. They result from the addition of extra nucleotides in a DNA sequence or chromosome.
When one or more nucleotides are inserted into the genetic sequence, the reading frame is disrupted during transcription, and eventually, translation. This may result in an altered sequence of amino acids, extra amino acid in a chain, or premature termination. Hence, the newly synthesized protein could be abnormally short, abnormally long, and/or contain the wrong amino acids. It will most likely not be functional.
Insertion of a larger sequence of nucleotide base pairs into a chromosome may occur when there is an unequal crossover during meiosis.