0.51 Bis2a 13.2 central dogma review:  (Page 12/31)

A silent mutation is a base substitution in the DNA sequence that, while different from the original, still codes for that same amino acid. This can happen because of the redundancy in the Genetic Code. While a given codon always codes for a specific amino acid, other codons may also code for that same amino acid. Codons that code for the same amino acid usually differ by only one base in their codon triplet. This means if a mutation happens at this location there is at least a one in three chance that it will also code for the same amino acid in the same place and there will be no change in the resulting protein.