Frameshift Mutation

Definition

A frameshift mutation is a genetic alteration that occurs when nucleotides are inserted or deleted from the DNA sequence, causing a shift in the reading frame of the genetic code. This change can drastically affect the resulting protein, often leading to a completely different amino acid sequence downstream of the mutation. It’s important because it highlights how changes in the DNA can have significant impacts on protein synthesis and functionality.

5 Must Know Facts For Your Next Test

1. Frameshift mutations can result from the addition or deletion of one or more nucleotides but not in multiples of three, which alters the entire downstream reading frame.
2. These mutations often lead to premature stop codons, resulting in truncated proteins that may be nonfunctional.
3. Unlike point mutations, frameshift mutations have a higher likelihood of causing significant changes in protein structure and function due to the extensive alteration of the amino acid sequence.
4. Frameshift mutations can arise from various factors, including environmental influences like radiation or chemical exposure and errors during DNA replication.
5. Some diseases, such as cystic fibrosis and certain cancers, can be caused by frameshift mutations that disrupt normal cellular processes.

Review Questions

• How do frameshift mutations differ from point mutations in terms of their impact on protein synthesis?
  • Frameshift mutations differ from point mutations primarily in their scale of impact on protein synthesis. While point mutations involve changes to a single nucleotide and may only affect one amino acid or leave the protein unchanged, frameshift mutations involve the insertion or deletion of nucleotides that shift the entire reading frame. This often results in a completely altered protein sequence downstream of the mutation, potentially leading to significant functional changes or loss of protein activity.
• Discuss the consequences of frameshift mutations on genetic variation and their role in evolution.
  • Frameshift mutations contribute significantly to genetic variation by introducing new sequences into the genome, which can alter traits and increase diversity within populations. These mutations can lead to new phenotypes that may provide advantages or disadvantages in specific environments. Over time, frameshift mutations can play a crucial role in evolution by driving adaptation and speciation as certain variations become favorable and are selected for in changing environments.
• Evaluate how understanding frameshift mutations can inform approaches to gene therapy for genetic disorders.
  • Understanding frameshift mutations is essential for developing effective gene therapy strategies for genetic disorders caused by these alterations. By identifying specific frameshift mutations associated with diseases, researchers can design therapies that correct or compensate for these genetic errors. Techniques such as CRISPR/Cas9 gene editing can be employed to restore the correct reading frame by repairing the mutated gene, potentially restoring normal protein function and alleviating disease symptoms. This knowledge allows for targeted approaches that could significantly improve treatment outcomes for patients with conditions linked to frameshift mutations.

Related terms

Codon:

A codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid or stop signal during protein synthesis.

Point Mutation: A point mutation is a change in a single nucleotide in the DNA sequence, which can lead to silent, missense, or nonsense mutations.

Genetic Variation: Genetic variation refers to differences in DNA sequences among individuals, contributing to diversity within a population and affecting traits and disease susceptibility.