Insertion/Deletion Mutations When a nucleotide is wrongly inserted or deleted from a codon, the affects can be drastic. In other words, every single codon would code for a new amino acid, resulting in completely different proteins coded for during translation.

Because an insertion or deletion results in a frame-shift that changes the reading of subsequent codons and, therefore, alters the entire amino acid sequence that follows the mutation, insertions and deletions are usually more harmful than a substitution in which only a single amino acid is altered.

Deletion Mutation Definition. A deletion mutation is a mistake in the DNA replication process which removes nucleotides from the genome. A deletion mutation can remove a single nucleotide, or entire sequences of nucleotides.

Without stop codons, an organism is unable to produce specific proteins. The new polypeptide (protein) chain will just grow and grow until the cell bursts or there are no more available amino acids to add to it.

They occur when the sequence of a stop codon is changed to specify an amino acid instead. When this happens, translation will continue until another stop codon is found. This results in a long protein that, again, is not usually able to function. Nonstop mutations would be like a traffic light that is always green.

Each three-letter sequence of mRNA nucleotides corresponds to a specific amino acid, or to a stop codon. UGA, UAA, and UAG are stop codons.

Insertion or deletion of three (or multiples of 3) nucleotides does not result in a frameshift mutation. It only results in the presence (or absence) of some amino acids in the polypeptide.

A frameshift mutation is a type of mutation involving the insertion or deletion of a nucleotide in which the number of deleted base pairs is not divisible by three. If a mutation disrupts this reading frame, then the entire DNA sequence following the mutation will be read incorrectly.

Sanger sequencing and pyrosequencing are two methods that have been used to detect frameshift mutations, however, it is likely that data generated will not be of the highest quality. Even still, 1.96 million indels have been identified through Sanger sequencing that do not overlap with other databases.

Frameshift products were found in the brains of patients with Huntington’s disease and transgenic mice (putatively in association with huntingtin aggregates), but were not found in normal brains or in brains with SCA2 or SCA7 brains containing aggregates.

Some scientists recognize another type of mutation, called a frameshift mutation, as a type of point mutation. Frameshift mutations can lead to drastic loss of function and occur through the addition or deletion of one or more DNA bases.

By inserting or deleting a single nucleotide from the RNA or DNA sequence, the groups of three nucleotides that the ribosomes read get messed up. This type of mutation only occurs when the number of changes is not a multiple of three.