AP BIOLOGY

Detailed explanation-1: -Silent mutations occur when the change of a single DNA nucleotide within a protein-coding portion of a gene does not affect the sequence of amino acids that make up the gene’s protein.

Detailed explanation-2: -Point Mutations A nucleotide change in the DNA that does not result in an amino acid change in the protein is called a “synonomous” or “silent” mutation (see Figure 3.3).

Detailed explanation-3: -Because silent mutations do not alter protein function they are often treated as though they are evolutionarily neutral. Many organisms are known to exhibit codon usage biases, suggesting that there is selection for the use of particular codons due to the need for translational stability.

Detailed explanation-4: -Point mutations that alter the resulting protein sequences are called nonsynonymous mutations, while those that do not alter protein sequences are called silent or synonymous mutations.