What is a nonsense mutation?

A nonsense mutation is a type of point mutation in DNA that results in a premature stop codon in the transcribed mRNA, leading to a truncated and often non-functional protein.

Here's a breakdown:

• What it is: A change in a single nucleotide within a gene sequence.

• The Effect: This change substitutes a single base in the original DNA sequence for another. The result is an altered mRNA sequence that codes for a non-functional protein.

• Premature Stop Codon: A stop codon signals the ribosome to halt protein synthesis. A nonsense mutation introduces a stop codon (UAA, UAG, or UGA) earlier than it should be, resulting in an abnormally short protein.

• Consequences: The resulting protein is usually non-functional because it lacks essential amino acids needed for its proper folding and activity. This can have significant consequences for the organism, depending on the function of the affected protein.

• Examples: Nonsense mutations can cause a variety of genetic disorders, such as some forms of cystic fibrosis, Duchenne muscular dystrophy, and beta-thalassemia.