Frameshift mutation

Frameshift Mutation

A frameshift mutation is a type of genetic mutation that involves the insertion or deletion of a number of nucleotides in a DNA sequence that is not divisible by three. This alteration shifts the "reading frame" of the genetic code, which can lead to significant changes in the resulting protein product.

A diagram illustrating a frameshift mutation.

Mechanism

In the genetic code, nucleotides are read in groups of three, known as codons, each of which codes for a specific amino acid. A frameshift mutation disrupts this triplet reading frame, causing all downstream codons to be read incorrectly. This can result in the incorporation of incorrect amino acids into the protein, potentially leading to a nonfunctional protein or truncated protein due to the introduction of a premature stop codon.

Diagram showing RNA codons and their corresponding amino acids.

Types of Frameshift Mutations

Frameshift mutations can occur through either:

• Insertion: The addition of one or more nucleotide base pairs into a DNA sequence.
• Deletion: The removal of one or more nucleotide base pairs from a DNA sequence.

Both types of mutations can have drastic effects on the phenotype of an organism if they occur within a coding region of a gene.

Consequences

The consequences of frameshift mutations can be severe, often resulting in genetic disorders or disease. For example, frameshift mutations are known to cause conditions such as cystic fibrosis, Tay-Sachs disease, and certain types of cancer.

Illustration of the translation process in genetics.

Comparison with Point Mutations

Frameshift mutations differ from point mutations, which involve a change in a single nucleotide base pair. While point mutations may only affect a single amino acid, frameshift mutations can alter the entire downstream amino acid sequence.

Diagram of a point mutation.

Detection and Analysis

Frameshift mutations can be detected using various molecular biology techniques, such as DNA sequencing and polymerase chain reaction (PCR). These methods allow researchers to identify and characterize mutations at the nucleotide level.

File:Frameshift mutations.jpg

Examples of frameshift mutations.

Related Pages

• Genetic mutation
• DNA replication
• Protein synthesis
• Genetic disorder
• Molecular biology