Frameshift mutation

Definition

A frameshift mutation is a genetic alteration where nucleotides are added or deleted from a DNA sequence in numbers not divisible by three, causing a shift in the reading frame of the genetic code. This alteration can lead to significant changes in the amino acid sequence during protein synthesis, often resulting in nonfunctional proteins or truncated versions, which can have serious effects on an organism's phenotype. It directly impacts how the information encoded in DNA is translated into proteins, highlighting its connection to the central dogma of molecular biology.

5 Must Know Facts For Your Next Test

1. Frameshift mutations can result from insertions or deletions of one or more nucleotides that are not multiples of three, disrupting the entire downstream reading frame.
2. These mutations can produce entirely different proteins than intended, as every amino acid after the mutation can be altered.
3. Frameshift mutations can lead to premature stop codons, resulting in truncated proteins that may not function properly.
4. The effects of frameshift mutations are typically more severe than point mutations due to their widespread impact on the resulting protein structure.
5. Common examples of diseases caused by frameshift mutations include certain types of muscular dystrophy and cystic fibrosis.

Review Questions

• How do frameshift mutations affect protein synthesis compared to other types of mutations?
  • Frameshift mutations have a more drastic effect on protein synthesis compared to point mutations because they change the entire reading frame of the genetic code. When nucleotides are inserted or deleted in numbers not divisible by three, every subsequent codon is altered. This often results in completely different amino acids being incorporated into the protein, which can lead to nonfunctional proteins or premature termination, severely impacting the organism's traits.
• Discuss the potential consequences of frameshift mutations on an organism's phenotype and health.
  • Frameshift mutations can have serious consequences for an organism's phenotype and overall health because they can create dysfunctional proteins or stop codons that truncate protein synthesis. For example, if a crucial enzyme is affected by a frameshift mutation, metabolic pathways may be disrupted, leading to various diseases. Conditions like muscular dystrophy and cystic fibrosis illustrate how such mutations can significantly impact bodily functions and lead to debilitating health issues.
• Evaluate how understanding frameshift mutations contributes to advancements in genetic medicine and therapies.
  • Understanding frameshift mutations is crucial for advancements in genetic medicine because it allows scientists and medical professionals to identify and target specific genetic disorders caused by these alterations. By using techniques like CRISPR gene editing or targeted therapies, researchers can potentially correct these mutations or compensate for the resulting dysfunctional proteins. This knowledge not only helps in developing treatment strategies but also enhances our understanding of genetic diseases' underlying mechanisms, paving the way for personalized medicine approaches.

Related terms

nucleotide: The basic building block of DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

codon: A sequence of three nucleotides that together form a unit of genetic code in DNA or RNA, specifying a particular amino acid.

point mutation: A change in a single nucleotide in a DNA sequence, which can lead to different effects than a frameshift mutation depending on its location and nature.