What is the general consequence of a frameshift mutation on the resulting protein?

• A. It introduces a premature stop codon.
• B. It changes only a single amino acid.
• C. It preserves the original reading frame.
• D. Frameshifts alter codon grouping and protein sequence.

Answer: (D)

Frameshift mutations happen when nucleotides are inserted or deleted in numbers not divisible by three, so the reading frame for codons shifts. This changes every downstream codon, producing a dramatically different amino acid sequence and often a truncated, nonfunctional protein. That core effect—altering how codons are grouped and rewriting the protein sequence downstream—is what makes this the general consequence. While a premature stop can occur in some cases, and a single amino acid change fits point mutations, those are not the typical outcome of a frameshift.