Explanation:
If each nucleotide determined an amino acid, we could only code four
different amino acids since in DNA there are only four different nucleotides. Figure very
less than the 20 different amino acids that exist.
If every two nucleotides will encode an amino acid, the total number of different dinucleotides
that we could achieve with the four different nucleotides (A, G, T and C) would be variations
with repetition of four elements taken two at a time VR4,2 = 42 = 16. Therefore,
we would have only 16 different dinucleotides, less than the number of amino acids
different that exist (20).
If each group of three nucleotides determines an amino acid. Given that they exist
four different nucleotides (A, G, T and C), the number of groups of three different nucleotides
that can be obtained are variations with repetition of four elements (the four
nucleotides) taken three at a time: VR4.3 = 43 = 64. Therefore, there is a total of 64
different triplets, more than enough to code the 20 different amino acids.
