Which mutation type introduces a premature termination during translation?

Which mutation type introduces a premature termination during translation?

• A. Frameshift
• B. Missense
• C. Silent
• D. Nonsense

Answer: (D)

Premature termination during translation occurs when a stop signal appears earlier than it should. A nonsense mutation directly changes a codon that normally codes for an amino acid into a stop codon, so the ribosome stops translating sooner and the protein becomes truncated. Missense mutations swap one amino acid for another, which can alter function but doesn’t inherently stop translation. Silent mutations don’t change the amino acid sequence at all. Frameshift mutations shift the reading frame and can drastically alter downstream codons and often lead to a premature stop as a byproduct, but the defining feature is the creation of a stop codon itself, which is what a nonsense mutation does.

Premature termination during translation occurs when a stop signal appears earlier than it should. A nonsense mutation directly changes a codon that normally codes for an amino acid into a stop codon, so the ribosome stops translating sooner and the protein becomes truncated. Missense mutations swap one amino acid for another, which can alter function but doesn’t inherently stop translation. Silent mutations don’t change the amino acid sequence at all. Frameshift mutations shift the reading frame and can drastically alter downstream codons and often lead to a premature stop as a byproduct, but the defining feature is the creation of a stop codon itself, which is what a nonsense mutation does.