Many of the amino acids are coded for by more than one codon. Examples are:
1. Isoleucine - ATT, ATC and ATA
2. Leucine - CTT,CTC,CTA CTG, TTA and TTG.
3. Valine - GTT, GTC, GTA and GTG.
4. Phenylalanine - TTT and TTC.
5. Cysteine - TGT and TGC
6. Alanine - GCT, GCC and GCG
7. Glycine - GGT, GCC, GGA and GGG.
8. Proline - CCT, CCC, CCA and CCG.
9. Threonine - ACT, ACC, ACA, and ACG.
10. Serine - TCT, TCC, TCA, TCG, AGT and AGC.