Differentiate between a silent, missense, nonsense, and frameshift mutation; provide an example of each and their likely phenotypic effect.

• A. Silent mutation: changes the amino acid; Example: GAA -> GAG (Glu); Effect: altered protein function.
• B. Missense mutation: introduces a premature stop codon.
• C. Nonsense mutation: changes a codon to a different amino acid.
• D. Frameshift mutation: insertion of one nucleotide shifts the reading frame; Example: insertion of one base; Effect: widespread amino acid changes and usually loss of function.

Answer: (D)