Diabetes is a disease characterized by the inability to break down sugars. Often a person with diabetes has a defective DNA sequence that messes up the code for making insulin. Suppose a person has a mutation in their DNA, and the first triplet for the gene encoding insulin is CCC (instead of CCA). Determine what amino acid the new DNA triplet codes

The new CCC codon codes for proline, while the original CCA codon also encodes for proline  

Explanation:

A synonymous substitution is a mutation produced by the substitution of one nucleotide for another in an exonic gene segment which doesn't modify the original amino acid in the protein sequence. Moreover, a silent mutation is any alteration in the nucleotide sequence that does not produce an observable effect on the organism's phenotype. The example above describes a synonymous substitution because the new codon (CCC) also codes for the same proline amino acid as the original non-mutated codon, thereby the resulting protein sequence remains unchanged. Consequently, in this case, mutations associated with diabetes are located at other gene regions. The genetic code is degenerate because different codons can code for the same amino acid.