Deletion mutation

Definition

A deletion mutation is a type of genetic alteration where one or more nucleotides are removed from a DNA sequence. This can lead to significant changes in the structure and function of proteins, as the reading frame of the genetic code may be shifted, potentially resulting in nonfunctional proteins. Understanding deletion mutations is crucial for grasping how genetic diseases can arise and how repair mechanisms try to correct such alterations.

5 Must Know Facts For Your Next Test

1. Deletion mutations can occur spontaneously during DNA replication or be induced by environmental factors such as radiation and chemicals.
2. The severity of a deletion mutation's effects often depends on its location; deletions in non-coding regions may have little impact, while those in coding regions can lead to severe consequences.
3. In some cases, deletion mutations can result in genetic disorders, such as cystic fibrosis or Duchenne muscular dystrophy, where crucial genes are affected.
4. Cells have evolved various repair mechanisms to detect and fix deletion mutations, including homologous recombination and non-homologous end joining.
5. When a deletion mutation occurs within a coding sequence, it can lead to truncated proteins or proteins with altered functionality due to changes in their amino acid sequence.

Review Questions

• How does a deletion mutation impact the structure and function of proteins?
  • A deletion mutation impacts protein structure by removing one or more nucleotides from the DNA sequence, which can shift the reading frame. This frameshift changes how the ribosome interprets the genetic code, potentially leading to an entirely different sequence of amino acids or even a premature stop codon. Consequently, this often results in nonfunctional proteins, significantly affecting cellular processes and overall organism health.
• What role do DNA repair mechanisms play in addressing deletion mutations, and what methods do they use?
  • DNA repair mechanisms play a critical role in addressing deletion mutations by identifying and correcting these genetic alterations to maintain genomic integrity. Techniques like homologous recombination utilize a template strand to accurately repair the deletion, while non-homologous end joining directly reconnects broken ends of DNA without needing a template. These repair processes help prevent the deleterious effects that could arise from persistent mutations.
• Evaluate the implications of deletion mutations in relation to genetic diseases and therapeutic approaches.
  • Deletion mutations can have profound implications for genetic diseases, as they often disrupt essential gene functions. This disruption can lead to conditions such as cystic fibrosis or muscular dystrophy, where missing or faulty proteins cause serious health issues. Understanding these mutations opens pathways for therapeutic approaches, such as gene therapy or CRISPR technology, aimed at correcting or compensating for the effects of deletions in affected individuals.

Related terms

Point Mutation: A point mutation is a change in a single nucleotide base pair in the DNA sequence, which can lead to amino acid substitutions or premature stop codons.

Frameshift Mutation: A frameshift mutation occurs when nucleotides are added or deleted from the DNA sequence, altering the reading frame and affecting all downstream amino acids in a protein.

DNA Repair Mechanisms: DNA repair mechanisms are cellular processes that correct damage to the DNA molecules, including those caused by mutations like deletions, ensuring genetic stability.