Frameshift mutation

Definition

A frameshift mutation is a genetic alteration where nucleotides are inserted or deleted from the DNA sequence, causing a shift in the reading frame of the genetic code. This shift can lead to significant changes in the resulting protein, as it alters how codons are grouped and read during translation, often resulting in nonfunctional proteins or truncated proteins that can cause diseases or disorders.

5 Must Know Facts For Your Next Test

1. Frameshift mutations can be caused by insertions or deletions of one or more nucleotides, but they are most impactful when the number of nucleotides deleted or added is not a multiple of three.
2. Because the reading frame is altered, frameshift mutations can change every amino acid downstream from the mutation site, often leading to drastic functional changes in proteins.
3. These mutations can result in serious genetic disorders such as cystic fibrosis and certain types of cancers due to the production of malfunctioning proteins.
4. Frameshift mutations are classified as either spontaneous, arising naturally due to errors during DNA replication, or induced, caused by external factors like radiation or chemicals.
5. Detection of frameshift mutations can be done using various molecular techniques, including sequencing and PCR methods, which help identify changes in the genetic code.

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 effect on the reading frame of the genetic code. While point mutations typically alter a single nucleotide and may result in silent, missense, or nonsense mutations, frameshift mutations change the entire sequence of amino acids from the point of mutation onward. This can lead to entirely different and often nonfunctional proteins, which can have serious consequences for cellular function and organismal health.
• What are some potential consequences of frameshift mutations on human health and development?
  • Frameshift mutations can have severe implications for human health and development. They can lead to diseases such as cystic fibrosis, where a mutation disrupts normal protein function essential for ion transport across cell membranes. The resulting dysfunctional proteins may cause developmental issues or metabolic disorders. Additionally, frameshift mutations are implicated in various cancers as they can produce aberrant proteins that drive uncontrolled cell growth.
• Evaluate the role of environmental factors in inducing frameshift mutations and discuss their implications for genetic stability.
  • Environmental factors play a significant role in inducing frameshift mutations through agents such as radiation and certain chemicals that interact with DNA. These factors can cause insertions or deletions during DNA replication, ultimately leading to genetic instability. The implications of these mutations for genetic stability are profound; increased frameshift mutations may contribute to tumorigenesis and hereditary diseases by disrupting normal gene function and promoting an accumulation of genetic errors over generations. Understanding these interactions helps in developing strategies for prevention and treatment of mutation-related diseases.

Related terms

nucleotide:

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

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

mutation:

Any change in the DNA sequence that can lead to alterations in the structure and function of proteins, which may impact an organism's phenotype.