The genetic code involved reading triplets; 4 different possibilities to code for the 20 amino acids; excess coding capacity. Comma-free; no spacing between one nucleotide to the next. 44 of the 64 combinations were potentially degenerate (amino acids specified by more than one codon) Codon: group of bases that specifies a single amino acid. The code is read in units of 3 nucleotides. 3 bases per codon (triplet) = 64 combinations. Synonyms: codons that specify the same amino acid. Degenerate: amino acids specified by more than one codon. E. g. cysteine has two codons, ugc & ugu. The standard genetic code: 61 of 64 codons encode amino acids, from 2-6 synonyms per amino acid, synonyms usually 3rd position wobble , 2nd position if more than 4 synonyms (e. g. leu, aug (met) is also start codon. A single point mutation could cause amino acid substitution e. g. agc ->aga causes ser ->arg. Degeneracy ->many mutations at 3rd codon position silent .