What is a frameshift mutation?

A frameshift mutation is a type of genetic mutation in which one or more nucleotides is inserted or deleted in a DNA sequence. This causes a shift in the reading of the codons in the mRNA, which also changes the way the DNA sequence is read. A DNA sequence is a chain made up of many smaller molecules called nucleotides. Inserting or deleting nucleotides in the coding region, alters the amino acid sequence at protein translation, resulting in phenotypic changes such as the production of an altered protein.