Frameshift mutation

Definition

A frameshift mutation is a genetic alteration that occurs when nucleotides are inserted or deleted from the DNA sequence in numbers not divisible by three, resulting in a shift in the reading frame of the genetic code. This change can lead to significant alterations in protein synthesis, potentially creating nonfunctional proteins due to the misalignment of codons during translation.

5 Must Know Facts For Your Next Test

1. Frameshift mutations can occur due to either insertions or deletions of nucleotides, but they specifically cause shifts in how the sequence is read during translation.
2. Because frameshift mutations alter the entire reading frame from the point of mutation onward, they can result in drastic changes to the amino acid sequence of the protein.
3. These mutations are often more damaging than point mutations because they affect all downstream amino acids, potentially leading to nonfunctional proteins.
4. Frameshift mutations can be caused by various factors, including exposure to certain chemicals, radiation, or errors during DNA replication.
5. Some diseases, such as cystic fibrosis and certain cancers, have been linked to frameshift mutations that disrupt normal protein function.

Review Questions

• How does a frameshift mutation impact protein synthesis compared to a point mutation?
  • A frameshift mutation causes a change in the reading frame of the genetic code due to insertions or deletions of nucleotides that are not in multiples of three. This results in altered codons downstream from the mutation site, potentially leading to a completely different sequence of amino acids and producing nonfunctional proteins. In contrast, point mutations typically affect only one codon and may result in a single amino acid change without affecting the rest of the protein's structure.
• Discuss the potential consequences of frameshift mutations on cellular function and organismal health.
  • Frameshift mutations can have severe consequences on cellular function as they disrupt normal protein synthesis by altering the amino acid sequence significantly. This can lead to dysfunctional proteins that may not perform their intended roles within the cell, potentially disrupting metabolic pathways and cell signaling. In terms of organismal health, such mutations are often implicated in various genetic disorders and diseases, impacting overall physiology and increasing susceptibility to conditions like cancer or inherited diseases.
• Evaluate how understanding frameshift mutations contributes to advancements in genetic research and medicine.
  • Understanding frameshift mutations is crucial for advancements in genetic research and medicine because it helps researchers identify the underlying causes of various genetic disorders. By analyzing how these mutations affect protein synthesis and function, scientists can develop targeted therapies and interventions for conditions caused by such mutations. Furthermore, this knowledge aids in genetic screening and diagnosis, allowing for early detection and potential preventative measures against diseases linked to frameshift mutations, thereby improving patient outcomes.

Related terms

Codon: A sequence of three nucleotides in mRNA that specifies a single amino acid or a stop signal during protein synthesis.

Point mutation: A mutation that involves a change in a single nucleotide base pair in the DNA sequence, which can lead to changes in the corresponding amino acid in a protein.

Nonsense mutation: A specific type of point mutation that converts a codon into a stop codon, leading to premature termination of protein synthesis.